Agenital

Agenital is a term for a rare intersex trait under the teresex umbrella in which one is born without visible genitals, due to being abnormally closed, underdeveloped, or absent (genital aplasia). The condition does not usually occur by itself, but is usually coupled with other conditions. It may or may not be coupled with gonadal agenesis.

Vaginal aplasia
Vaginal aplasia is when someone with a typically female body has little to no genitallia. It is estimated to occur amongst 1 in ever 4,000 AFAB individuals, and many with this condition seek out surgical assistance later in life (if they weren't altered as an infant) since this isn't always the lack of genitals, and can instead be just very little build to ones genitals.

Penile agenesis
Penile agenesis is when someone with a typically male body has little to no genitallia. This is estimated to occur in between 20-30 million AMAB births. One with this condition almost always needs to have surgical intervention, as they usually have no urinary outlet.

Cryptorchidism
Cryptorchidism is when someone with a typically male body is missing one or more testicle, or when one or more of the testicles have formed inside of the body rather than outside. There is currently no findable estimate of this occurence in AMAB births. One with this condition likely also has hypospadias. When one only has one testicle, the condition is often referred to as Monorchism.

One with a singular testicle can still be functional enough to produce enough testosterone and sperm to induce pregnancy and fertility.

Aphallia
Aphallia is a term for someone who is born without a phallis. This includes Penile agenesis while also including those with a typically female body who are born without a clitoris. It is a rare condition with very little reports, however this is likely due to fear of stigmatization, since intersex conditions are often looked at in a negative way.

Other Definitions
Agenital is sometimes used interchangeably with angenital, which is an altersex identity in which one desires to be without genitals.

It is occasionally used to refer to asexuals who are repulsed by genitalia but are not necessarily not devoid of sexual feelings or repulsed by other sexual acts that do not primarily involve genitals.

Resources

 * https://www.sciencedirect.com/topics/medicine-and-dentistry/vagina-aplasia
 * https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485865/
 * https://en.wikipedia.org/wiki/Aphallia
 * https://en.wikipedia.org/wiki/Penile_agenesis_and_testicular_agenesis
 * https://en.wikipedia.org/wiki/Cryptorchidism
 * https://en.wikipedia.org/wiki/Monorchism