Google+ seemed like a boys club at first, but recent estimates point to a growing number of women using the Internet search giant's social networking service.

Just this week, Paul Allen of FamilyLink and Ancestry.com fame said a third of Google+ users are now female.

That's a big jump from previous guesses that put the percentage at a quarter, a tenth or even less. Allen's estimates, which use census data and statistics on the frequency of certain last names occurring within the overall U.S. population, have proven to be surprisingly accurate. Previously, Allen correctly predicted that total Google+ users would soon exceed 10 million.

"The poster of 18 men in a hot tub that has been passed around for the past week or two is not reflective of reality and is not what Google+ is going to end up being," Allen wrote on Google+.

But even if Allen's numbers are right, the percentage of Google+ users who are female would still lag the percentage of users of other popular social networking sites who are female.

A Pew report puts the split of Twitter users at 64 percent female. Pew says MySpace and Facebook also have 57 percent and 58 percent female users, respectively. Only LinkedIn has a male majority, with just 37 percent female users.

One theory on the dearth of women on Google+ has to do with the nature of the field test.

From the beginning, it has been dominated by tech industry insiders, and in particular by engineers, according to a survey that found it to be the most popular profession among Google+ users. Both the tech industry and especially software and hardware engineering tend to be dominated by men.

But as the social network has gradually expanded and more friends, family and colleagues are invited, the percentage of women has risen.

Regardless of how women are finding their way to Google+, they're arriving and they're beginning to organize. The site "Women of G+" has emerged with the declaration that "33 percent of Google+ users are women and 100 percent of us are awesome."

Amen. Er, A-women.