you have 5-alphareductase [sic] deficiency and so you grew a penis at age 12.

No you didn't.

This was easy to throw away. Here's one of the first sources that came up:

Many people with 5-alpha reductase deficiency are assigned female at birth based on their external genitalia. In other cases, affected infants are assigned male at birth based on their external genitalia, often an unusually small penis (micropenis) and the urethra opening on the underside of the penis (hypospadias). Still other affected infants may be assigned either female or male at birth as their external genitalia do not look clearly male or clearly female.

During puberty, an increase in the levels of male sex hormones leads to the development of some secondary sex characteristics, such as increased muscle mass, deepening of the voice, development of pubic hair, and a growth spurt. The penis and scrotum (the sac of skin that holds the testes) may grow larger. People with 5-alpha reductase deficiency do not develop much facial or body hair. Most affected individuals are unable to have biological children (infertile) without assisted reproduction.

So, due to genetic deformities, an infant may have been misidentified. As a result you did not grow a penis from whole cloth, but your micropenis (a deformity) may have enlarged.

This subversive is, once again, attempting to claim that what you are and what you are initially considered are exactly the same thing. In reality, you were a genetically deformed male, misidentified as female.

I'm not going to go onto the rest of this because this is always the same sophistic structural argument in every half-factoid that the OP is trying to hurl at you.

Don't use science to justify your bigotry. The world is way too weird for that shit.

These same people: "All white people are racist. This is scientifically proven."

When you assert anything they don't like with a boundary condition; they claim that each individual edge-case invalidates the boundary entirely. The fact that you have a definition (which are inherently socially constructed because they are language devices) it proves that the fundamental nature you are describing is not nature at all and is fully arbitrary and abstract.

When they assert a boundary condition; it is a universal truism and is unquestionable. It is axiomatically the case in all times, places, cultures, and worlds; and is describing a fundamental understanding of the universe. Each assertion is as objectively true as the gravitational constant.