That would indeed prove to be a problem in their current situation, and in the foreseeable future too. Jim didn't see his life changing anytime soon, and a ship was definitely no place to raise a baby— much less so a pirate ship. He didn't even bother thinking whether or not having a child would be something he wanted, simply because he knew that they couldn't. Not if she wanted to stay on the ship.

"Mr. Spock can't talk when I've more than once walked in on him sharing very intimate moments with Uhura," Jim answered lightly but pointedly. Not that he'd care either way, he'd do what he wanted no matter what. "Why Mary, how often do you think of taking me when I'm sitting in my chair up there?"