I found this article and thought it looked like fun. DH and I are team Green so we won't be finding out which means I'm having lots of fun with the 'alternative' means of gender testing.
http://www.geekinheels.com/2011/04/26/the-gender-guessing-game.html
Being a Social Worker, I did actually look at the research article that Ramzi wrote and it all looks pretty legit to me! Enjoy!