How do you find the house of new parents?

You look for the house with its keys left in the door overnight.
You look for the house with all the front windows open (done the same night as the keys left in the door).
Follow a couple home who both have dark circles under their eyes, but the baby is well rested.
Follow a man with spit up on ALL of his work shirts.
Look for the house getting lots of orders from diapers.com.
Follow the woman home from the grocery store who sways in line but has no child in her arms.
Bring up poop and if the person isn't disgusted and can talk about it for more than 5 minutes you have found a new parent.