The Intersex Society of North America classifies "congenital adrenal hyperplasia" as an intersex condition. They note:
Congenital Adrenal Hyperplasia (CAH) is the most prevalent cause of intersex among people with XX chromosomes. About 1 in 10,000 to 18,000 children are born with congenital adrenal hyperplasia, but it does not cause intersex in those with XY chromosomes, so the prevalence of CAH-related intersex is about 1 in 20,000 to 1 in 36,000.
Among the many causes of intersex, only CAH represents a real medical emergency in the newborn period. Click here to read about the medical risks of CAH both at birth and later in life.
CAH occurs when there is a broken genetic "recipe" for making cortisone in the adrenal glands (the glands on top of the kidneys that make various hormones and add them to the blood stream). Because the recipe is broken, the adrenal glands, while trying to make cortisone, may make an unusually high level of other hormones that are "virilizing". That is, they can make XX embryos have larger than average clitorises, or even a clitoris that looks rather like a penis, or labia that look like a scrotum.