Due to a hormonal variation, babies with 5 ARD deficiency, or 5 alpha reductase-3 deficiency, are born with XY chromosomes but may appear typically female at birth, developing masculine secondary characteristics at puberty.

With Androgen Insensitivity Syndrome, or AIS, babies with XY chromosomes are born with bodies that are unable to respond to androgens. Children with CAIS, or Complete Androgen Insensitivity Syndrome, may appear typically female at birth while those with PAIS, or Partial Androgen Insensitivity Syndrome, may appear somewhere on the spectrum between a typical male or female body.

Babies with CAH, or Congenital Adrenal Hyperplasia, are often born with uterus and ovaries, but their genitalia may appear masculinized with a shallow vagina present. CAH is caused by the adrenal gland failing to make an enzyme needed for regulating androgen, aldosterone, and cortisol. People with CAH may suffer from severe salt-wasting which can be life threatening if not treated.

Complete Androgen Insensitivity Syndrome. See AIS

With epispadias the meatus, or urethral opening, is located on the upper surface of the phallus

Hypospadias occurs when the urethral opening is on the underside of the phallus somewhere between the tip and the base of the shaft rather than at the tip. With an epispadias, the urethral opening is on the upper surface of the phallus.

People with Klinefelter syndrome are born with an additional chromosome resulting with XXY rather than a typical XY, resulting in reduced muscle mass, less facial hair, and reduced testosterone.

Mayer-Rokitansky-Küster-Hauser, or MRKH, results in children having an atypical vagina, uterus, and fallopian tubes, but can also affect bone and heart development.

With ovotestis, people are born with a combination of a testis on one side and an ovary or ovotestes on the other. Ovotestis are gonads that are composed of both ovarian and testicular tissue. Their genitalia may appear typical for male or female babies at birth or fall somewhere between the two.

Partial Androgen Insensitivity Syndrome. See AIS.

People with Swyer syndrome are born with XY chromosomes, however their testes do not develop normally and instead they may be born with female appearing genitalia and a uterus.

Turner syndrome occurs when an X chromosome is missing. Infertility is common without medical help.

See Klinefelter syndrome