1. You will spend a crazy amount of time clipping their weed-like fingernails, even though your own nails don't grow worth a damn.
2. They will also probably have nicer eyelashes than you.
3. Little-boy funk-smell kicks in sometime around age 3.
4. It smells like a combination of feet and maple syrup.
5. You will totally get peed on. In the face, directly, at least once.
6. I also do not suggest painting the walls immediately around changing tables or toilets with a flat finish. Go with eggshell or satin, or else just thumbtack up some freaking towels.
7. Those little PeePee TeePee things do not work, unless you care to see just how far your son's urine can propel a tiny, soggy cone of fabric across the room.
8. All that said, a lot of times they just manage to pee right on their own heads. Memorize their shocked expression when it happens, because hiiiiiiiiiilarious.
10. Yeast infections are not just for girls.
12. The instinct to turn random objects into guns/blasters/lasers/phasers/swords/lightsabers/arrows/cannons/etc. is something they are born with. Don't worry about it too much.
13. Buy helmets, though.
14. Remember that one mean little girl in first grade who would randomly announce that she wasn't your friend any more; she was someone ELSE'S friend now and you couldn't be friends with either of them because she said so and made you cry but then the very next day the rules were all completely different?
15. There are mean little boys like that, too.
16. The good news is that once you're a grown-up you realize it's perfectly okay to think that they're annoying little sh*ts and tell their moms on them when they color on your walls with markers.
17. Even after many mature, frank discussions about body parts and the differences between boys and girls, you will definitely be asked -- loudly and publicly -- about your own lack of a penis and whether or not you pee out your butt.
18. At some point, you'll have to sack up and send them into the mens' room by themselves. This is both amazing and terrible.
19. Wearing a dress makes you look beautiful, Mommy. A single sequin on your shirt or a sparkly necklace earns you an upgrade to princess. Your hair looks gweat. Your hugs are nice. Your cuddles are the best. I wuv you, Mommy.
20. Ugh, they are so awesome, it hurts.