By what month is the sex of the fetus usually evident?

The sex of the fetus is generally evident by the end of the third month of pregnancy, which is when most prenatal ultrasounds can first reliably reveal the biological sex. Around this time, the external genitalia have developed enough to be distinguishable, making it possible for trained medical professionals to identify whether the fetus is male or female with reasonable accuracy.

While the development of the fetus continues significantly into the second and third trimesters, the formation of the sex organs occurs during the first trimester, with the differentiation becoming visible around the conclusion of the third month. As a result, by this time, parents often have the opportunity to learn about the sex of their baby through imaging techniques. Later months may provide clearer views, but the basic identification starts to be possible in the third month.