Final answer:
A son has a 50% chance of being colorblind if his mother carries the trait. The probability of a straight hairline is not determinable without information on the parents' genotypes for that trait.
Step-by-step explanation:
The chance of a son being colorblind and having a straight hairline depends on the combination of alleles he inherits from his parents. Colorblindness is an X-linked recessive trait, which means a son can only inherit this trait from his mother if she carries the allele. Since colorblindness is not associated with hairline shape, the probability of inheriting both traits needs to be considered separately.
The provided information tells us that a son of a woman who carries the colorblindness trait has a 50% chance of being colorblind. Assuming that straight hairline is determined by a separate gene with a simple dominant-recessive relationship, and without any information provided about its inheritance or the parents' genotypes for this trait, we can't accurately calculate the son's chances of having a straight hairline in combination with color blindness.