My DM has handed down some corkers over the years:
Attending funerals when pregnant is very dangerous (accompanied by wide eyed, knowing look, but no further explanation).
Newborns need to be left to scream as it's good for their lungs.
BF on one side for three minutes precisely, then swap to the other side. Repeat ad infinitum.
BFing more often than every four hours will spoil a baby.
BFing for longer than four weeks will spoil a baby.
If you talk to your baby too much, they'll never learn to talk themselves.
If you carry baby too much, they'll never learn to walk.
All babies should be potty trained by 18 months, like you all were (I distinctly remember two of my siblings having toileting issues for years, probably due to this too-early training).
You should get their hearing checked if they're not talking fully by 18 months.
I could go on all day.....