Is sperm really good for you or are guys just saying that so girls will suck them off?
There are NO health benefits to swallowing semen. Myspace/Facebook posts are running abound on the supposed health benefits of engaging in any type of sexual activity -- I mean, it's not like the people there, or in real life, have anything to gain from misinforming young girls to believe positive gobbledygook (most of which often caters to improving some aesthetic aspect/appearance, which is actually way negative, but that's another rant) so that they're more likely to score online and off, right?
But seriously: if you hear anything like that, you're being fed a line. The only benefits you'll get from swallowing semen is if YOU find it sexy and choose to do it because you like it, and go on to enjoy it. The drawbacks aren't so pretty, and include negative effects like sexually transmitted infections, some of which are serious. In fact, you're set to win this fabulous prize even if you don't swallow -- pre-ejaculate contains just as many pathogens, and we're not even mentioning the infections transferred by skin contact versus fluid, like herpes. THERE's that picture-perfect smile we were promised for performing fellatio!
Teeth whiter? Skin shinier? Healthier heart? All those? Brush your teeth, take a shower, go for a jog. Much less risky, much healthier, and of nobody's benefit but yours, which, when we're talking YOUR body, is all it should be for.