Ambiguous genitalia is a rare form of intersex affecting 0.05% of the population, causing them to have both female and male sexual organs.
People with ambiguous genitalia are also sometimes known as hermaphrodites, though that term is generally considered offensive as it tends to generalize them and act as if them having ambiguous genitalia is the only interesting thing about them. It also stigmatizes the topic and encourages fetishists.