Genetics is an essential field of biology that explains how traits are inherited and expressed in living organisms. It plays a critical role in understanding heredity, evolution, and modern applications such as genetic engineering and personalized medicine. Since the foundational work of Gregor Mendel, genetics has become a core component of science education. In the Philippine K–12 curriculum, genetics is taught in Senior High School biology subjects to develop students’ understanding of heredity and genetic variation. Scientific literacy, which includes genetics literacy, is necessary for students to make informed decisions about health and biotechnology (Organisation for Economic Co-operation and Development [OECD], 2023). According to Dougherty et al. (2021), genetics literacy enables individuals to understand genetic information and apply it in real-world contexts.

Understanding genetics is fundamental to the study of biology because it explains how traits are inherited and expressed in living organisms. Consequently, developing a strong understanding of genetic concepts is considered an important component of scientific literacy (Cary & Branchaw, 2017, as cited in Rusmana et al., 2021). Despite its importance, genetics remains one of the most difficult biology topics for students to master. The subject involves abstract and microscopic processes that cannot be directly observed, which increases cognitive demands on learners. Studies show that students develop misconceptions about genes, chromosomes, DNA, and inheritance (Walter et al., 2021). Misconceptions are persistent incorrect beliefs that differ from scientifically accepted explanations and may interfere with meaningful learning (Todd & Romine, 2022). Additionally, enhancing students’ understanding of genetics requires greater attention within the educational system because the concepts involved are complex and often difficult for learners to grasp (Duncan & Reiser, 2007, as cited in Rusmana et al., 2021).

Recent research has shown that students commonly believe that dominant traits are stronger than recessive traits, that genes alone determine traits without environmental influence, and that acquired characteristics can be inherited (Opfer et al., 2022). These misconceptions may result from abstract concepts, ineffective teaching strategies, and prior knowledge (Tibell & Rundgren, 2020). If misconceptions are not corrected, they may persist and affect future learning (Dougherty et al., 2021). Therefore, it is important to identify genetic misconceptions among senior high school students. Although previous studies have identified the students’ misconceptions in genetics and related biological concepts, research continues to affirm the fact that misconceptions concerning genetics are common among secondary school students. For instance, studies conducted on the conceptual understanding of genetics concepts by students revealed that the majority of the students only have fragmented knowledge of genetics information, which makes them lack the ability to integrate the concepts of genes, DNA, and inheritance into a scientific explanation. The fragmented knowledge, therefore, contributes to the formation of misconceptions that are common among students (Machová et al., 2023). In addition, research studies have shown that a majority of secondary school students lack a conceptual understanding of genetics, with the majority of the students being characterized by misconceptions, even after the topic is taught (Ojo, 2024).

Recent literature has also highlighted that genetics is a subject that is most prone to misconceptions due to the abstract ideas, complex scientific terminology, and processes that occur at microscopic levels that cannot be directly observed. These characteristics make genetics difficult for learners to conceptualize and often lead to incorrect interpretations of genetic phenomena (Maysyaroh et al., 2025). Moreover, misconceptions in biology education have been identified as major barriers to students’ ability to apply scientific knowledge effectively, thereby hindering meaningful learning and scientific literacy development (Guerra-Reyes, 2024). Despite the growing body of literature on genetics misconceptions, most existing studies have focused on identifying misconceptions among general secondary students or university learners in different educational contexts. There remains limited research that quantitatively examines the prevalence and nature of genetic misconceptions among Senior High School students within specific curriculum frameworks. Therefore, further investigation is necessary to identify the common genetic misconceptions held by Senior High School STEM students. Consequently, this study aims to determine the genetic misconceptions and level of conceptual understanding among STEM students. The findings of this study will serve as a basis for proposing a Genetics Misconception Remediation Worksheet (GMRW) that may help address the identified learning gaps and improve students’ conceptual understanding. Specifically, this study sought to determine the students’ level of conceptual understanding in genetics, identify common misconceptions, and propose a Genetics Misconception Remediation Worksheet (GMRW) based on the findings.

Constructivist Learning Theory

Constructivist Learning Theory explains that learners actively construct knowledge based on prior experiences and existing ideas. According to constructivist perspectives, misconceptions arise when learners interpret new information using incomplete or incorrect prior knowledge. Recent studies in science education emphasize that learners develop scientific understanding through active engagement, reflection, and interaction with learning experiences rather than passive reception of information (Guerra-Reyes, 2024). In genetics education, students often develop misconceptions because genetics concepts involve abstract and microscopic processes that are difficult to visualize. Research further suggests that misconceptions persist when students are unable to connect new scientific explanations with their prior understanding (Machová & Ehler, 2023). The theory therefore supports the importance of identifying students’ misconceptions and designing remediation activities that allow learners to reconstruct scientifically accurate understanding.

Conceptual Change Theory

Conceptual Change Theory explains how learners replace misconceptions with scientifically accepted concepts through guided instruction and reflective learning. The theory posits that conceptual change occurs when learners recognize inconsistencies between their existing misconceptions and scientifically accepted explanations. Contemporary studies in biology education emphasize that conceptual change strategies are effective in addressing persistent misconceptions in genetics and molecular biology (Todd & Romine, 2022). Similarly, Ojo (2024) reported that students’ misconceptions in genetics may be reduced through instructional interventions that encourage conceptual clarification and reflective thinking. In the context of this study, the proposed Genetics Misconception Remediation Worksheet (GMRW) aims to promote conceptual change through clarification activities, guided exercises, visual representations, and reflective learning tasks that encourage students to re- evaluate their existing understanding of genetics concepts.

Conceptual Change Framework

The study is anchored in the Conceptual Change Framework, which explains how learners replace misconceptions with scientifically accepted concepts through reflective learning and instructional intervention. Conceptual change occurs when students recognize inconsistencies between their existing knowledge and scientific explanations, leading them to reconstruct their understanding of concepts. Recent studies in science education emphasize that misconceptions in biology and genetics persist because students often rely on fragmented prior knowledge and intuitive reasoning when interpreting abstract scientific concepts (Machová & Ehler, 2023). Genetics concepts are particularly prone to misconceptions due to their abstract nature, complex terminology, and microscopic processes that cannot be directly observed (Maysyaroh et al., 2025). Moreover, research has shown that identifying misconceptions is essential in designing targeted remediation strategies that promote meaningful learning and improve conceptual understanding among students (Guerra-Reyes, 2024). Therefore, the present study utilized the Conceptual Change Framework to explain how the identification of students’ misconceptions through the Genetics Conceptual Understanding and Misconception Test (GCUMT) and Certainty of Response Index (CRI) served as the basis for developing the proposed Genetics Misconception Remediation Worksheet (GMRW).

Figure 1. Conceptual Change Framework of the Study

This study employed a quantitative descriptive research design to determine the level of conceptual understanding and common misconceptions in genetics among Grade 12 STEM students. Quantitative methods allow the systematic collection and analysis of numerical data, making them appropriate for assessing students’ conceptual understanding and identifying misconceptions (Creswell & Creswell, 2023). The descriptive approach was utilized to describe the students’ level of conceptual understanding and determine the misconceptions commonly held in genetics. Descriptive research is appropriate when the purpose of the study is to identify and describe characteristics, trends, and conditions within a population (McCombes, 2023). The respondents of the study consisted of Grade 12 Senior High School students enrolled in the STEM strand. Grade 12 STEM students were selected because they had already completed Biology 1 and were currently taking Biology 2, where genetics concepts are introduced and reinforced. Their prior and ongoing exposure to biology content made them appropriate participants for assessing conceptual understanding and misconceptions in genetics. The total population of the study consisted of 332 Grade 12 STEM students. To determine the appropriate sample size, the researcher utilized the Raosoft Sample Size Calculator (Raosoft Inc., 2004) using a 95% confidence level, 5% margin of error, and 50% response distribution. The use of appropriate sample size estimation procedures is supported in methodological literature to ensure the reliability and generalizability of findings (Memon et al., 2020). Based on these parameters, the computed sample size was 152 respondents. Simple random sampling was employed to ensure that each member of the population had an equal chance of being selected, thereby minimizing bias and improving the representativeness of the sample (Creswell & Creswell, 2023).

The study utilized a researcher-made Genetics Conceptual Understanding and Misconception Test (GCUMT) designed to assess students’ conceptual understanding and identify possible misconceptions in genetics. The development of the instrument was guided by the learning competencies in the Senior High School General Biology 2 curriculum, particularly topics on patterns of inheritance, central dogma and DNA, and genetic engineering (Department of Education, 2020). The instrument was also informed by studies identifying common misconceptions in genetics, including misunderstandings related to gene–DNA–chromosome relationships and inheritance patterns (Machová & Ehler, 2023; Ojo, 2024). The GCUMT consisted of 30 multiple-choice items with four options and one correct answer. The instrument was complemented by the Certainty of Response Index (CRI) adopted from Hasan et al. (1999), as cited in Duda et al. (2021) and Ojo (2024), which measured students’ confidence levels in answering each item. The identification of students’ misconceptions was based on the Certainty of Response Index (CRI), which determines the respondents’ level of confidence in answering each test item, as shown in Table 1. The classification of students as having conceptual understanding, misconceptions, or a lack of understanding was based on the CRI interpretation criteria shown in Table 2.

establish validity, the instrument underwent content and face validation by biology educators, science teachers, and research specialists. A Table of Specifications (TOS) was also prepared to ensure alignment between the test items and the learning competencies in the curriculum. After validation, the instrument was pilot-tested among Grade 12 STEM students who were not included in the actual study. Reliability testing using Cronbach’s alpha yielded a coefficient of 0.93, indicating excellent internal consistency and reliability of the instrument. Recent studies emphasize that validity and reliability testing are essential in establishing the psychometric quality of educational research instruments (Ramírez-Montoya et al., 2024). Prior to data gathering, the researcher secured the necessary permissions from the school administration and informed the respondents about the purpose of the study. Participation was voluntary, and informed consent was obtained from the respondents. Confidentiality, anonymity, and proper handling of the gathered data were strictly observed throughout the conduct of the study. The collected data were analyzed using frequency counts, percentages, mean percentage scores, and the Certainty of Response Index (CRI) to determine students’ conceptual understanding and identify misconceptions in genetics.

This section presents the findings of the study regarding the level of conceptual understanding and genetic misconceptions among Grade 12 STEM students. The results were organized according to the objectives of the study, specifically the students’ level of conceptual understanding in genetics, the identification of misconceptions using the Certainty of Response Index (CRI), and the proposed Genetics Misconception Remediation Worksheet (GMRW).

Table 3 presents the distribution of the test questions according to the identified genetics topics and learning competencies included in the Senior High School General Biology 2 curriculum. The organization of the test items ensured alignment between the assessment instrument and the intended curriculum competencies. The table further shows that the instrument covered major genetics topics, including inheritance, molecular genetics, and genetic engineering, which allowed the researcher to identify areas where students demonstrated conceptual understanding and misconceptions.

Table 4 presents the percentage on the level of conceptual understanding in genetics among Grade 12 STEM students. The findings revealed that the respondents generally demonstrated conceptual understanding in genetics, with an overall average percentage of 80.72%, interpreted as “Understands Concepts.” Among the identified topics, the highest conceptual understanding was observed in DNA Structure and Proteins with 89.03%, followed by Patterns of Inheritance with 88.17%. Meanwhile, the lowest level of conceptual understanding was observed in DNA Replication and Protein Synthesis with 64.52%, interpreted as “Moderately Understands Concepts.” The findings suggest that students experienced greater difficulty in understanding abstract molecular genetics processes compared to observable inheritance patterns.

Table 5 presents the identified misconceptions of Grade 12 STEM students based on the Certainty of Response Index (CRI) analysis. The findings revealed that several misconceptions were evident among the respondents, particularly in topics related to modified Mendelian inheritance, DNA structure, protein synthesis, and genetic engineering. The presence of incorrect answers with high confidence levels indicated that students possessed firmly held misconceptions rather than mere lack of knowledge. The results further suggest that students may struggle in connecting abstract molecular genetics concepts with scientific explanations, leading to scientifically inaccurate interpretations.

Table 6 presents the proposed Genetics Misconception Remediation Worksheet (GMRW) developed based on the findings of the study regarding the conceptual understanding and genetic misconceptions of Grade 12 STEM students. The proposed worksheet is intended to serve as a supplementary remediation material that may help address the identified misconceptions and learning difficulties in genetics. The development of remediation activities was anchored on the identified misconceptions revealed through the Certainty of Response Index (CRI) analysis and the students’ level of conceptual understanding. The proposed Genetics Misconception Remediation Worksheet (GMRW) aims to help reduce students’ misconceptions and strengthen their conceptual understanding in genetics through targeted remediation activities aligned with the identified learning gaps in the study.

The findings revealed that Grade 12 STEM students generally demonstrated an acceptable level of conceptual understanding in genetics. Students showed strong understanding in topics related to Mendelian inheritance, DNA structure, and genetic engineering. However, students experienced greater difficulty in understanding DNA replication and protein synthesis. The lower conceptual understanding in these topics may be attributed to the abstract and microscopic nature of molecular genetics concepts. Tibell and Rundgren (2020) explained that molecular biology concepts are difficult for students to visualize because they occur at microscopic levels that cannot be directly observed. The presence of misconceptions among students further supports previous studies indicating that genetics is one of the most misconception-prone areas in biology education. Misconceptions identified in the present study involved dominant and recessive traits, modified Mendelian inheritance, DNA structure, protein synthesis, and genetic engineering. Similar findings were reported by Ojo (2024), who found that secondary school students continued to demonstrate misconceptions in genetics even after instruction.

The findings also support Constructivist Learning Theory, which explains that misconceptions develop from learners’ prior knowledge and experiences. Students may construct incorrect explanations when abstract concepts are not effectively clarified through instruction. Likewise, Conceptual Change Theory emphasizes the importance of remediation activities in helping learners replace misconceptions with scientifically accepted concepts. Based on the identified misconceptions, the proposed Genetics Misconception Remediation Worksheet (GMRW) was developed to strengthen students’ conceptual understanding through guided activities, visual learning materials, concept clarification, and reflective learning tasks. Guerra-Reyes (2024) emphasized that targeted remediation strategies may help reduce misconceptions and improve meaningful learning in science education.

The study determined the level of conceptual understanding and genetic misconceptions among Grade 12 STEM students. Findings revealed that students generally demonstrated an acceptable level of conceptual understanding in genetics. However, misconceptions remained evident in several complex and abstract areas of genetics, particularly DNA replication, protein synthesis, and molecular genetics. The study further revealed that misconceptions persisted even among students who demonstrated confidence in their responses. These misconceptions may hinder meaningful learning and scientific literacy development if not properly addressed. Based on the findings, the study proposed a Genetics Misconception Remediation Worksheet (GMRW) to help address misconceptions and improve conceptual understanding among students.