My mum laughs at my baby!

It’s actually getting on my nerves and makes me sad when she does that. She would walk into a room, see my baby and start laughing. Prior to me getting pregnant, she always “jokingly” told me that my husband is “ugly”. Since, my baby has been born, she hasn’t stopped mentioning that my baby looks exactly like her father... now, she goes as far as laughing every time she sees my baby. This hurts my feelings a lot and I really don’t know how to tell her this because she probably does not mean any harm