It's kind of weird how King Bowser has like eight kids but we've never seen their mother. I got to thinking, though...
Yoshi is referred to as male, but lays eggs.
Birdo is supposed to be biologically male, but spits eggs out of her mouth.
Is there something we don't know about reptiles in the Super Mario Universe? Could gender be merely a social construct to them? Does Bowser lay eggs?
I... I think I broke my brain. :(