17-AH Deficiency

17-AH Deficiency or 17-alpha-hydroxylase deficiency is an intersex condition in which the adrenal glands- the glands that regulate the production of certain horomones- do not properly function. Because of this, the reproductive system does not grow very strongly. This condition is estimates to effect 1 in a million individuals at birth.

Those with XX chromosomes (individuals who would typically be AFAB) have abnormally small ovaries and an abnormally small uterus. Because of this, they do not grow many secondary sex traits, such as breasts, pubic hair, or menstruation. Because of this, they are unable to concieve a child, and thus are infertile.

Those with XY chromosomes (individuals who would typically be AMAB) usually have ambiguous genitals or a vagina, and because of this, they are often mistaken as female. Those that do have a penis often have a micropenis, cryptorchidism, and/or hypospadias. They are also infertile.

Genetics
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. This means the parents each have one cell with this condition, and both the cells combined is what effected the child when being concieved.

Resources

 * https://medlineplus.gov/genetics/condition/17-alpha-hydroxylase-17-20-lyase-deficiency/#synonyms
 * https://en.wikipedia.org/wiki/17%CE%B2-Hydroxysteroid_dehydrogenase_III_deficiency