Key learning points

1. Some alleles are associated with conditions that affect people’s health (e.g. cystic fibrosis).
2. Prospective parents can be tested for these alleles, as can embryos (embryo screening).
3. A fetus can be tested for these alleles (e.g. by chorionic villus sampling or amniocentesis).
4. Tests can have false negative or false positive results, and risks of miscarriage or infection.
5. Parents must be supported to interpret test results, consider ethical questions and make difficult personal decisions.

Keywords

• Allele - different version of a gene, which can produce a different characteristic in the organism’s phenotype

• Genetic testing - processes that look for the presence of particular alleles in the DNA of an organism’s genome

• Carrier - a person with one copy of a recessive allele (they won’t show the characteristic but can pass the allele to their offspring)

• Probability - the likelihood that something will happen, which can be calculated as a decimal number between 0 and 1

• Ethical question - a question about whether something is right or wrong

Common misconception