Intersex is a general term used for a variety of situations in which a person is born with reproductive or sexual anatomy that doesnt fit the boxes of female or male. Sometimes doctors do surgeries on intersex babies and children to make their bodies fit binary ideas of male or female. Doctors always assign intersex babies a legal sex (male or female, in most states), but, just like with non-intersex people, that doesnt mean thats the gender identity theyll grow up to have. This brings up questions about whether or not its OK to do medical procedures on childrens bodies when its not needed for their health.
Being intersex is a naturally occurring variation in humans, and it isnt a medical problem therefore, medical interventions (like surgeries or hormone therapy) on children usually arent medically necessary. Being intersex is also more common than most people realize. Its hard to know exactly how many people are intersex, but estimates suggest that about 1-2 in 100 people born in the U.S. are intersex.
https://www.plannedparenthood.org/learn/gender-identity/sex-gender-identity/whats-intersex