Ehh, swear words in English are mostly just coarse and vulgar terms themselves, and they DO have words that are considered unsuitable for broadcast.
But generally I think it's more important to translate with the audience in mind. If it's a kid's show, don't translate "yarou" as something that wouldn't be acceptable to a kid audience in English. You don't have to go all S&P on that ****, but just consider whether you want your 5-year-old nephew asking what "bastard" means before you slip it into that Gingaman script.
As far as hilariously inappropriate profanity goes, the one that always sticks in my mind is the old, bad Elite-Fansubs version of Hikaru no Go, that had Akira -- the soft-spoken, intelligent young Go prodigy -- shouting **** OFF (all caps) at the protagonist. Ahh, good times.