My 3yo son that is. He's always been a headbutter...not in a mean way, but when he gets rowdy and playful he headbutts. It's something we're working on, but he still does it a lot. Yesterday I was being silly with him and chasing him around the house and I jumped out from around a corner to "scare" him and he headbutted me right in the crotch. His forehead met my pubic bone...HARD. His head is fine, but I woke up this morning with a giant, swollen bruise on my lady parts. It hurts to sit, walk, wipe, wear jeans, etc. This sucks.