Where did Jesus' Y Chromosome come from?

So a while back, an acquaintance tagged me in the comments of this Facebook post:

I was really at a loss as to why he’d think this is genius, but the more confusing response comes from tereziinateacup

If you believe that God created all time, space and matter out of NOTHING (Latin: “ex nihilo”), why would you be confused as to how God could create a single little Y chromosome?