I need advice on my mother in law. please help!?

I was always close with my husbands parents and had no problem getting along with them, they did alot for us getting established on our own and i really appreciate them. however; once my son was born they now feel the need to tell us how to raise him and its driving me crazy! i have kept my mouth shut to avoid an argument with them or my husband (who does stand up and take my side) but im at the point i cant take it anymore. they tell me my 10 month old shouldnt have a sippy cup and should still be on only bottles bc hes a 'baby' and they buy bottles and give him koolaid (which he doesnt need) in bottles when we are @ their house. they insist he needs old fashioned 'walking shoes' instead of being barefoot when learning to walk and say we dont feed him enough when we clearly do and he is a perfect weight according to his dr. if i give them info to support my decisions they say they dont care they ave raised kids. its hard to talk to them bc they dont back down and i know it will turn into a fight. they humiliate me @ family gatherings etc. by saying how i do things wrong. we usually sped alot of time @ their house (they live 5 minutes away) but i can no longer go over there or it will be ww3. i need advice. he is OUR child. my husband tells them constantly but they just say they have raised kids, we have not. we both constantly tell them 'no bottles' 'he doesnt need 3 jars of babyfood at once' 'he doesnt need to be in shoes in summer' etc. and they insist they are right and brush us off. i certainly dont want to keep their grandson from them by any means but they have pushed me to where i dont want to be around them and they dont keep my son, they only see him when i am there. i dont want to argue but i dont know what to do... it clear that just talking to them doesnt work.