Table 1.

Sequences of information required by different family members

Level 1: Information required by all family members	1. Genes for a recessive disorder may be inherited from parents and ancestors
Level 2: Information required by carrier couples to make informed choice about future children	1. Both parents carry one gene for a recessive disorder
	2. One-in-four risk in every pregnancy of having an affected child
	3. Prenatal diagnosis may be available to detect if child is affected/unaffected
Level 3: Information required by carrier parents to pass onto their children to ensure they are able to make informed choices about genetic testing, partner choice and future children	1. Carrier parents may pass on their gene for the recessive disorder to their children
	2. Unaffected children may carry the same recessive gene
	3. Genetic test may be available to detect carrier status of unaffected persons
	4. Unaffected persons who are carriers could have affected children if their partner also carries the same recessive gene
	5. A blood relative is more likely to carry the same recessive gene than an unrelated person
Level 4: Information required by carriers to pass onto siblings and other extended family members to ensure they are able to make informed choices about genetic testing, partner choice and future children	1. The recessive gene has been transmitted through family ancestors
	2. Siblings of a carrier, and their children, may also carry a gene for the same disorder
	3. Genetic test may be available to detect carrier status of unaffected relatives
	4. A person who is a blood relative is more likely to carry the same recessive gene than an unrelated person