I'm sorry, but it blows my mind how many u/s techs are taking guesses at the gender of babies at 12- 14 weeks. Take a look at these pictures taken from this website....http://baby2see.com/gender/external_genitals.html
Can you tell which is male and female. I can't. These are the development pictures from 12-14 weeks. Even the site says the guess is still 50/50.