i think you also need to look at where they are in the family..
Mr M is so very clever and talks very clearly (with out bias is a bit ahead of most boys his age) but he was the first child first grand and great grandchild. so for almost 2 yrs he had solid one on one input from every one.
Miss A was second (with a 3rd following 3 weeks latter) she isn't gettting the same quality as mr M did.
but knowing how quick it has gone i have been more willing to let her do things at her own pace rather then push her along(ykwim). but she to is showing signs of great early language skills.(has a vocab of 25/30 words)

But yes there is a difference between the sexes any way. i have just finished reading raising boys and it goes in to it a fair bit there.