Since these are gene questions, I know there are no absolute answers, so I’m only asking for an educated guess to each.
I have red hair, as does my brother, and our mother. The assumption of why he and I both inherited mom’s hair color instead of dad’s brown is that Dad is 1/3rd Scottish, which seemed to have mixed well with mom’s Irish half…(he also has a lot more red haired family members then she does, since her grandmother is the only other on her side of the family). Does the fact that we both inherited mom’s coloring make us(and our future spouses) more likely to have red haired babies than the average person? Would our spouses’ nationalities affect this much?
Had my mother and father had more children (let’s say two more) would the fact that both of their existing children were born with red hair make these hypothetical children more or less likely to also have red hair?
My brother is nearly ninteen and worried that his hair is getting darker (I think that he’s merely comparing it to my hair which is bleached by the sun, while his isn’t). Is it possible that it will change to brown on him now that he’s an adult? If so, how old would he have to be before his only worry will be if it turns gray?