That headbutting was genetic?  I'll let you in on a little secret.  Once upon a time, in his younger, crazier days, Kevin was somewhat predisposed towards headbutting things.  (generally after a few drinks).  I never suspected that it was genetic!  Tyler has entered a phase where, when he gets mad he will headbutt things (usually the floor, after throwing himself down in a fit of anger).  We try to catch his head when he does this, but sometimes he's too fast, and twice he has split his forehead open.

He also does it when he is really excited and wound up.  He will come racing across the room, throw himself into your arms, and lay a headbutt on you that would do a pro wrestler proud.  He caught me by surprise a few days ago and practically broke my nose!  We are trying to discourage this, and so far our "hugs not headbutts" campaign seems to be working...

BTW, his uncle Ken used to do the same thing when he was little.  (I went the route of kicking things, instead)