The baby’s gender is determined at the moment of fertilization, but it won’t be detectable until the 4th or 5th month of pregnancy, since the reproductive organs are not yet developed.
At this week 3, the embryo is still very small, about the size of a pinhead.
The fertilized egg continues to divide for about 30 hours after conception. It implants into the uterine lining 5 to 8 days later. This may cause mild cramping or light spotting.