The fact that Dante's Inferno features an achievement awarded for killing unbaptised babies might sound horrendous, but to be fair they are pretty ugly babies.
Pretty ugly babies with knives for arms, to be exact, and I'm not sure there is a court anywhere that would prosecute you for kicking a few of them as they waddle towards you, swinging about their razor-sharp appendages menacingly. Executive Producer Jonathan Knight spoke of this achievement yesterday at EA's Naughty and Nice holiday press event during a discussion of the game's finer points, which aren't just breasts and the odd bit of phallic architecture.
The achievement is similar to the "Kill 1,000 Children" achievement in Fairytale Fights, which might not make it into the final game. I wouldn't worry about EA taking away the "Bad Nanny" achievement though. After all, they've got one of the greatest literary works of all time backing them up.