We found out at 17 weeks. I asked at our 12 week scan but the sonographer looked at me like I was an idiot and aid it was way too early.
I would say it was your sonographer that was an idiot. as I said earlier, I have read heaps of stuff lately that say the gender can be seen at 12 weeks with pretty high rates of being correct. I haven't time now but I will find it later & post. Im sure it was like 93% right.