You can be male because you were born female, but you have 5-alpha reductase deficiency and so you grew a penis at age 12.

No, XX genetic females will not grow a penis at age 12 or any other age due to 5-alpha reductase deficiency.

Males (XY) born with this deficiency suffer from genital atrophy at birth and are typically assigned female. A few of them who produce enough testosterone might develop a micro penis at puberty onset.

This is not "a gender variation", it is a genetic abnormality.

You can be female because you have an X and a Y chromosome but your missing the SRY gene, and so you have a female body

Males (XY) born with a defective Y chromosome with a pathogenic SRY (or an SRY deletion) might express external female genitalia, but do not develop functional ovaries.

This is not "a gender variation", it is a genetic abnormality.

You can be male because you have two X chromosomes- but also a Y.

These are males with a genetic pathology known as Klinefelter syndrome.

This is not "a gender variation", it is a genetic abnormality.

You can be female because you have only X chromosome at all.

These are females with a genetic pathology known as Turner syndrome.

This is not "a gender variation", it is a genetic abnormality.

And you can be male because you have two X chromosomes, but your heart and brain are male.

There is no scientifically documented of this claimed "condition".

In conclusion, she cites a list of well known genetic abnormalities that are pathological corner cases that end up supporting the general rule, that there are two genetically determined sexes in healthy humans.