7) Inherited Disorders

• It is now possible to test unborn foetuses for a range of genetic disorders. However, this means that the parents may have to make difficult decisions about the future of their baby. There is also a small risk to the pregnancy when removing foetal cells to test.
• Some human disorders are inherited and are caused by the inheritance of certain alleles:

  Polydactyly (having extra fingers or toes) is caused by a dominant allele.

  • Cystic fibrosis (a disorder of cell membranes) is caused by a recessive allele.