The probability is completely independent of whether or not the first child is a boy. When you toss a coin 99 times and get 99 heads, the probability of the next toss being a head is still 50%. However the chances of getting 100 heads in a row in the first place are very low.
Don't think there are any other biological factors to worry about here, the fertilised egg has even chances of gotting a Y chomosome as it has of not getting it.
|