I just went through the same thing, and the way I dealt with was:
I talked to my wife and told her that either she or me would have to talk to her mother, and let her know that while her knowledge and input was welcomed, all the decisions were made by us, and that for her to offer her opinión she would have to be consulted by us. I had to put a stop to it because she was making all the decisions for my wife, against my judgement, and we both made mistakes.
Obviusly my wife talked to her, and she took it very well.
By the way I have been taking my 1 month old daughter, to family gatherings every week since she was born, and everything has been fine.
Just make sure that there aren't any sick kids.View Thread