Can the baby's be determined at 12 wks by a 3d ultrasound?

I go on Jan 30 when i am (supposed to be) 12 weeks to the doctor, and i believe i am having a sonogram- and they have 3d ultrasounds at my doctor. however- - if i was possibly 13 or 14 wks along ( i did not see the dr at the first appt-4 wks- but the nurse thinks i was 4 wks, but i was not examined or anything)... anyway if i am 12 weeks or possibly a little further can the doctor tell the of my baby? is it easier to determine with the 3d ultrasound? Thanks!!!