Yes, there is sperm in precum. Not many, but it only takes one... remember the film from health class, lol? Not to mention other risks (thinking of the STD muppets on Chappelle's Show).

Sure, doing the horizontal mambo sans-raincoat sure is fun! And so is picking out baby names, woohoo! Maybe try picking out names while you're 'warming up' uncovered... multitasking is an outright barrel of monkeys!