Fetal ultrasound imaging is an extremely significant and effective testing technique for monitoring the fetus' growth and development in the mother's womb. In order to get the greatest results, anticipating parents must be knowledgeable about fetal ultrasound, including vital fetal ultrasound milestones.

The formation of the fetus's gender occurs at the moment the egg and sperm meet. According to the principle: an egg carrying the X chromosome meets a sperm carrying the X chromosome, forming an XX zygote – female gender. Conversely, an egg carrying the X chromosome meets a sperm carrying the Y chromosome, forming an XY zygote – male gender.