The term for the sex of a fetus in English is gender. Gender refers to the social and cultural expectations and roles assigned to individuals based on their biological sex.
Determining the gender of a fetus has become a common practice in many countries through the use of ultrasound technology. An ultrasound is a non-invasive procedure that uses high-frequency sound waves to create images of the developing fetus. Through an ultrasound， medical professionals can determine the sex of the fetus by identifying the presence of male or female genitalia.
Gender identification can also be done through invasive prenatal testing， such as chorionic villus sampling (CVS) and amniocentesis. These tests involve taking a sample of fetal cells from the placenta or amniotic fluid and analyzing its DNA. These tests are typically done for medical reasons， such as detecting genetic disorders， but can also reveal the sex of the fetus.
However， it is important to note that the determination of fetal gender can be controversial. Some argue that it reinforces gender stereotypes and can lead to sex-selective abortions in some cultures. In addition， there is a growing movement towards the use of gender-neutral language and the recognition of gender diversity beyond the binary categories of male and female.
In conclusion， the term for the sex of a fetus in English is gender. However， the concept of gender is complex， and its determination can have significant social， cultural， and ethical implications.
