Just as an example, here is research that says otherwise:
http://www.sciencedaily.com/releases/2010/01/100121135904.ht...
The researchers found no evidence of gender-based parenting abilities, with the "partial exception of lactation," noting that very little about the gender of the parent has significance for children's psychological adjustment and social success.
Another example:
http://news.discovery.com/human/genetics/parents-gender-chil...
Children usually benefit from having two parents instead of one. The gender of each parent, however, does not have a significant impact on a child's success.