I recently went to the funeral of a 100 year old female relative on my dad's side. My dad and pretty much all of his male cousins and uncles where bald. Figured that was a classic case of getting it from the females. Maybe in your case it was from an X passed down through female lines for several generations with no males getting it until you got "lucky". Since women have two X maybe the other males on your mom’s side got the non balding one and in my dad’s relatives case they all hit their odds and got the balding X.

Very interesting on the spiders! We think we know how things work but good to crunch the numbers to see if we need a new theory. I was reading something a while back about the classic model of crossovers perhaps only applying to males. But then snakes are like birds and the females are the ones with the mismatched gender chromosomes (w and z) and so they determine the gender of the offspring. So maybe in other things you would need to swap the gender genetics when comparing to mammals.

I tried to get some data on gender distribution once and was just told that it's 50/50 in the long run. Even if that is the case as expected it would be interesting to plot the distribution and see if it's the expected normal curve or concentrated at the ends.

Maybe the females don't produce each egg randomly as expected but do something like copy a smaller number of eggs. In the spider case maybe spider sperm are bad swimmers but spider eggs cells are favored somehow.