How to keep my dog from growling at the male humans, especially my husband?

We've had our new female dog for a month now. She is 2 yrs old and a "rescue" from Katrina. We think she is wonderful. She is well behaved, house broken, etc. Except for the fact that she growls at men! Especially, my husband. She has attached herself to me as her "Alpha", and follows my 3 1/2 yr old daughter around like they are best buds. She is fine with my mother, and my other grown daughter, but she growls at my grown nephew and at my husband, and the growling is getting a little louder. She has not tried to "snap" at any one, but it is worriesome. Other than that, she is a great dog. I do not know much of her situation before we got her other than she basically lived in a crate, and may have been abused before she was rescued (she cowers if you raise your voice or your hand and she hates the rolled up newspaper!). It has taken her a while to get used to everyone, but she has adapted wonderfully, except for her growling at the guys. She appears to be a Black Lab and Dalmation mix