How long in the pregnancy can you tell the sex of the child?

By ultrasound : Depends on the us tech. Nevertheless sex differentiation can be seen from 16 wks on.

Depends: How bad do you need to know and how much cash can you invest? There is a maternal blood test often referred to as NIPP.It can identify fetal cells circulating in mothers blood as early as 8 weeks and chromosome studies can be done on these (inclusing sex). The parts are formed by 12 wks but can seldom be reliably reported on ultrasound until 16-20 wks.