The one that throws me is: If you are a parent (say a father), and DO NOT have a child of the same sex as you (a son in this case), you have broken an unbroken

The one that throws me is: If you are a parent (say a father), and DO NOT have a child of the same sex as you (a son in this case), you have broken an unbroken line of parents before you who had a child of the same sex. Every father that came before you had at least one son that lived to have their own children, and had a son... It's simple but blows my tiny mind. My mother was quite shocked when she learnt the female line broke with her. :P