Analyzing the pattern of inheritance for a genetic condition can help determine the mode of inheritance. If a genetic condition is not present in either parent but is sometimes inherited by their offspring, the condition is likely –

. If a genetic condition is not present in either parent, it is never inherited by their offspring. But when either parent is affected by the condition, their offspring have at least a 50% chance of inheriting it and the condition is likely –
. If a genetic condition is more readily expressed by male offspring than female offspring, the condition is likely –
.

X-linked recessive. If a genetic condition is equally likely to be passed on to male and female offspring, the condition is likely – autosomal dominant or autosomal recessive.