Two Peas in a Pod
A Case of Questionable Twins
Singapore American School
Based on an actual event, this case study focuses on some of the problems associated with reproductive technologies. It tells the story of the "Joneses," who after in vitro fertilization treatment, discover that their fraternal twins are less similar than one would expect two brothers to be. Students work in teams to unravel the mystery using DNA profiling. Related issues that can be explored include the right to medical information, the implications of human error, and racism.
- Review the terms and concepts of fertilization, twinning, fraternal vs. identical twins, in vivo and in vitro fertilization, and DNA profiling.
- Interpret evidence from several single locus DNA gel electrophoresis tests.
- Understand the benefits and limitations of reproductive technology.
- Explore legal and ethical issues implied by the use of reproductive technology.
KeywordsTwins; twinning; fertilization; heteropaternal superfecundation; reproductive technology; in vitro fertilization; IVF; gel electrophoresis; DNA profiling; paternity; maternity; medical error; bioethics; medical ethics
Topical AreasEthics, Legal issues, Social justice issues
Educational LevelHigh school, Undergraduate lower division
Type / MethodsInterrupted, Role-Play, Trial
Subject HeadingsBiology (General) | Molecular Biology | Biotechnology |
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