[Rio]

Whichever one the baby just came out of... That’s the mother.
I don’t care what they call the other one.

[so_real]

There are hereditary diseases carried on both the X and the Y chromosomes. It's important to know who donated them when there is a fear of a child having such a disorder. The birth certificate is not supposed to be a "participation ribbon" that everyone gets just to feel good about themselves ...