as soon as you can be 100% sure of gender is when they are born. before that you do have to rely on the skill and experience of the ultrasound technician. six weeks is a little early to offer a definitive answer (we used to affectionately call this "weiner hunting") so be patient. your baby will either be a boy or a girl. there is nothing you can do to change it now.
how early can you tell gender? . using a 3d ultrasound how early can you tell the gender of your baby? can you tell at 6 weeks along?