If a man with achondroplasia and a normal woman children, what is the likelihood of having dwarfs?

50%: If one parent has achondroplasia, a child has a 50 percent chance of inheriting the fgfr3 gene and subsequently developing achondroplasia. If both parents have the disorder, the child has a three in four (75 percent) chance of developing achondroplasia. Also, in these cases, the child has a one in four chance of inheriting the gene from both parents. Newborns who inherit both genes are considered.

Achondroplasia: Achondroplasia is an autosomal dominant genetic disorder. For people with achondroplasia there is a 50% chance that their offspring will have the same disorder.