At my 12 week apt they told me what they thought the gender was, but couldn't guarantee it. Since both girls' and boys' parts look exactly the same at this time, apparently the angle gives a clue to the gender. Girls' parts will be more parallel to their spine and boys' will be more perpendicular (more than 30% angle). We'll see after my next scan if they were right!
The anatomy scan is usually closer to 20weeks
There are blood tests you can do from 10 weeks on that can tell you the gender. Here is North America though they cost 500$ (they are primarily used as screening tests for Down syndrome etc but they can also tell you the gender)
12 weeks is too early to see the gender in a scan,in the UK you can have a private scan to find out but only from 16+ weeks