Genetics: Analysis and Principles 5th Edition by Robert Brooker

Exercise 60

Ectrodactyly, also known as "lobster claw syndrome," is a recessive disorder in humans. If a phenotypically unaffected couple produces an affected offspring, what are the following probabilities
a. Both parents are heterozygotes
b. An offspring is a heterozygote
c. The next three offspring will be phenotypically unaffected
d. Any two out of the next three offspring will be phenotypically unaffected.