This is just a theory … A vanity plate theory.

The man observed that his wife has birthed only boys and is perhaps proud, so he wants to publicly label her, himself or both of them as “boy breeder.”

It’s the only way I can make it make sense in my head, but sometimes I can be a bit oblivious, so take it with a grain of metaphorical salt.

Apparently it’s a real name but as to why you’d choose it… no fucking clue. Not unless he’s in a school with people named Tanner, Tucker, Bartholomew and Rupert Shitgrain Esquire