Your research team suspects that lactose intolerance is a recessive trait. Which of the following observations would contradict your theory?

Question

a) Two lactose intolerant parents always have children who are lactose intolerant

b) Genetic analysis shows that individuals must possess two copies of the "lactose intolerance gene" to show the lactose intolerant phenotype

c) Two parents, both lactose intolerant, have a child who is not lactose intolerant

d) Two parents, one able to tolerate lactose and the other intolerant, have a child who is able to tolerate lactose

e) Two parents, one able to tolerate lactose and the other intolerant, have a child who is not able to tolerate lactose

Answer 1

I would think the answer is C.
If lactos intolerance is recessive, then both parents, who are lactose intolerant, can only pass on the intolerance genes to the offspring. So, as far as I can tell, they could not have an offspring who can tolerate lactose.