One in every 1,500 babies is born with atypical genitalia to the point where a specialist is required to determine the sex of the child. Historically, these babies were called Hermaphrodites.
A hermaphrodite is an organism that is able to be either male or female as required such as some invertebrates and many plant species.
That is not the case in humans, so we use the term “Intersex”.
Intersex literally means between the sexes and is not used exclusively for those born with obvious sexual ambiguity. Many more people are born with subtle sex organ variations some of which won’t show up until much later in life.
The causes of these sexual deviations are many and varied and are explained more specifically as Disorders of Sex Development (DSD).