Every minute of every day, a baby is born. Most babies are easily seen to be a girl or a boy. Imagine how confusing it must be when we don't know the sex of a newborn?
This is rare, and it can be very upsetting for parents. What causes this to happen and what can be done? The information here can answer questions about ambiguous genitalia.
Female Reproductive System
Male Reproductive System
What Does "Ambiguous Genitalia" Mean?
Sex organs develop with three basic steps. If something goes wrong with this process, a sexual development disorder (DSD) can happen. DSDs are caused by hormones. Genitals can develop in ways that aren't normal looking. They can be unclear or "ambiguous." A baby can have features from both genders. The medical term "intersex" is also used to describe ambiguous genitals.
The sex of a baby can be tested to help parents raise a child. Surgery can be used to help clarify a baby's gender.
Please note: DSD's are not the same as transsexualism. A transsexual is a person who doesn't see themselves as their defined gender. DSD's are different. They are caused by hormones that change the way a fetus develops.
How Do Genitalia Normally Form?
Sex organs develop with three basic steps:
- The genetic sex is set when the sperm fertilizes the egg. An XX pair of chromosomes means that the baby is female. An XY pair means that the baby is male.
- Next, gonads (sex glands) form into either testis for a boy or ovaries for a girl.
- Then, the inner reproductive system, and outer genitals develop. Hormones from either the testis or ovaries shape the outer genitals.
At conception, the mother shares an X chromosome and the father an X or Y chromosome. The pair creates either a female embryo (XX), or a male embryo (XY). At this point, the male and female embryos look the same.
Embryos start with two gonads. They can become either testes or ovaries. Each embryo also starts with both male and female inner genital structures. They become male OR female reproductive structures.
For girls, very little change is needed for the vagina to look normal. The vagina forms right away, before the ovaries have fully formed. For boys, a series of steps must take place. This starts with the growth of testes. The cells of the testes must begin to make testosterone, the male hormone. Then a more powerful hormone (dihydrotestosterone or DHT) causes genital tissues to change. It forms the slit-like groove of the urethra. Then the penis, which was first the size of a clitoris, becomes larger. The tissue on either side forms into the scrotum. Later, the testes move down into the scrotum. At the same time, structures known as mullerian ducts form inner organs. They either become fallopian tubes and a uterus (in a girl), or disappear (in a boy).
All of these steps take place during the first three months of pregnancy. After that, the outer sex organs look like either a penis or vagina.
DSDs can be passed down from a parent, or have no clear cause.