Textbook case of how seemingly innocuous hiring practices -- like asking interview questions about zombies and superheroes, in a room with a "funny" name or decor -- can lead directly to an almost total lack of gender diversity.In business, you are what you do EVERY DAY. You stand for the values you live EVERY DAY.

how would divide company culture versus bias? 

Company culture IS a set of biases. 

Every thing the company does is going to attract some people and repel others. 

I think it's a well dispelled myth that women play less computer games than men.  http://www.themarysue.com/women-gamers-spend-equal-on-games/

That may be true, but it's also true that fewer women are getting computer science degrees these days.

By the way, Dropbox is exceptionally bad when it comes to bro culture:

Indeed, the trend is getting worse. In 1985, 37 percent of computer science undergraduate degree recipients were women. By 2011 this proportion had dropped to 18 percent. Most technology firms refuse to release gender and diversity numbers. Data collected on Github explains why. Dropbox, for example, had only 9 women in its 143 person engineering team as of October 2013. That’s 6.3 percent in an industry in which 18 percent of the hiring pool is women.

Dropbox recently completed $250 million of funding at a valuation close to $10 billion according to the Wall Street Journal. It is rumored to be heading towards an IPO. The company has been expanding its hiring yet the number of women in management is declining. Kim Malone Scott, who headed operations and sales, left in April 2013; Anna Christina Douglas, who headed product marketing, left in August; and VP of Operations Ruchi Sanghvi left the company last October.

Two former female employees and one current employee of Dropbox shared their concerns with me. They asked not to be named because they had signed non-disparagement agreements and feared negative consequences for their careers if they spoke critically of Dropbox. One wrote in an e-mail, “When I interviewed for Dropbox, I was interviewed in a room called ‘The Break-up Room,’ by a male. It was right next to a room called the ‘Bromance Chamber.’ It felt weird I would be interviewed in such a strangely named conference room.” She said that “every time the company holds an all hands ‘goals’ meeting, the only people who talk are men. There are no females in leadership. The highest ranking is a team lead on the User Ops team.”