• While watching kids projectile puke in the most amusing ways on AFV, you laugh yourself stupid (and your wife runs to the bathroom crossing her legs), when once you would turn the channel in disgust.
• The contents of a diaper are dinner table conversation. Interesting dinner table conversation.
• You buy three pacifiers per week ("binkies" in our house), every week, for four months, and yet can only find one at any particular time.
• You give your child the rapper name, "diapah killah"
• Children's toys puzzle and intrigue you long after the child has moved on.
• Your kids room looks better than yours (yeah, we know, not for long).
• You can sing songs from no fewer than seven childrens shows. In harmony.
• The pets start circling the kid like fuzzy-tailed vultures during dinner.
• You finally realize bedtime is for wimps. You can sleep when you're dead.
• The cheap stroller you got from "Toys R Big Bux" is more popular than the soopa-stroller you spent two weeks stalking on e-bay .
• Your child has more, and better, clothing than you do.
• You hide when your child detonates while your "no! We love you guys, and we love your kids too!" best-friends are holding them. (Swear to God guys, all you had to do was ask)
• You can guess how many times your kid has peed into a diaper by the weight of it alone.
• You score concert tickets out of sympathy (thanks Nina, Richie, & Billy!)
• You leave your brother-in-law with your sleeping child, knowing a door slam is an automatic wakeup call, just so your wife can come home from shopping to see her tough-guy brother in a desperate panic saying, "no no no no baby please please please please don't cry don't cry!"

And that's just for infants. God knows what the older parents know about...