Forty percent of US gamers are female, according to a survey carried out by the Entertainment Software Association.

The ESA has released its 2008 Essential Facts About the Computer and Video Game Industry, and revealed some other rather interesting stats on the contemporary gaming market.

While the media worries about how gaming is effecting children, the survey found that the average age of a gamer is now 35 years old, with 25% of gamers being over 50. Boys aged 17 and under only represented 18% of gamers.

The study also focused on concerns about parents and their children’s game consumption, stating that 94% of parents are present during kid’s game purchases, and 64% actually believe that games are a positive part of their children’s lives.

The study also concludes via NPD data that only 15% of games sold last year were rated “M” for mature by the ESRB.

"This new data underscores the fundamental principle that computer and video games are a mainstream entertainment form, which captures the imagination of every segment of our society," said ESA CEO Michael Gallagher. "No longer is there a stereotypical gamer.”

For the full survey, download the PDF from the ESA website.