Genital warts are caused by a virus - which are much harder to knock on the head than bacteria.
You'll usually know if you've got genital warts cos you'll see (and maybe feel) them. You can also get them around your anus. Usually they're not painful and they probably don't do you any serious harm.
Still, warts aren't a great look - especially there. If you've got them, your doctor might suggest painting them with a solution or freezing them. Sometimes they come back, but not always, and sometimes they even go away by themselves.
Using a condom won't give you total protection from genital warts. That's because they're spread by skin rubbing together - they haven't invented a condom big enough to stop that yet! So it doesn't hurt to run a quick 'visual' over your partner before getting down to business.