A man, homozygous for curly hair reproduces with his wife who has straight hair, what's the hai

The gene for hair texture is incompletely dominant, which means the phenotype is a blend of the two parental types.

(This is different from codominant, in that codominance expresses *both* dominant traits instead of an intermediate between the two. The easiest example of this is the ABO blood types, in which the dominant trait is always expressed over the recessive trait (O). So if someone is AO, the recessive one gets thrown out and they just have type A blood. If someone is AB though, they express type A *and* type B, there is no blend between A and B with codominance.)

So with incomplete dominance in the hair trait, the intermediate between curly and straight is wavy, which will be expressed.

A man, homozygous for curly hair reproduces with his wife who has straight hair, what's the hair of the child

more often than not, it's the woman's side that determines the hair. my mom's side is massively curly, and my dome is like a brillo pad if i let it grow.

A man, homozygous for curly hair reproduces with his wife who has straight hair, what's the hair of the child

The question doesn't give enough information. Which allele is dominant or are they codominant.

I think hair genes are codominant so the child will have wavy hair in between curly and straight.

A man, homozygous for curly hair reproduces with his wife who has straight hair, what's the hair of the child

Assuming curly hair is the recessive trait, and the dad's genotype is (ss). If the mom is homozygous for straight hair (SS) the child's hair is straight (Ss). If she is not then the child's hair can be straight (Ss) or curly (ss).

But like most traits, more that one gene may affect the phenotype. So, my answer only works if they aren't codominant, if more that one gene doesn't affect the trait, and if they don't show incomplete dominance. The child's hair may be intermediate between the two parents (wavy).