Does a transgender retain his original DNA after hormone treatment and/or transformation operations?

Answer

Hi Eric,

First some (simplistic) background information about DNA and how it directs our body to let you discover the answer for yourself:
Humans (just like other living organisms that you can see around you with the naked eye) consist of trillions (10^12) cells with exactly the same package of DNA in each cell. This DNA contains the information about how that gigantic pile of cells can form a human (or a tree or a cow or…). Part of such a package of DNA also tells how an embryo in the womb should make a male or female sex organ (determined by Y or X chromosome).
However, there are many steps between the ‘DNA tells’ and ‘how do I look’ with a huge number of possible influences (including from outside) at each step, each of which can be very decisive. The DNA is therefore the starting point of what someone might look like, but so many extra things are added to that that the outcome is no longer determined by the DNA alone. Conversely, the way you look is not translated back into the DNA: the DNA is a constant. While you now look completely different as an adult than when you were a baby, you still have the same DNA as when you were born (with the exception of mutations due to, for example, dangerous radiation).

To compare it a bit with cooking, the DNA is the recipe in the cookbook; each body is then specialized in a specific chapter eg. ‘desserts’, whereby a liver cell with exactly the same DNA as a brain cell looks very different and does very different things. And by just reading the recipe, you don’t have a cake yet: the right ingredients and actions have to come together and only when it all comes together correctly, you have a cake. For cells, these are specialized proteins that convert substances (eg hormones) and it is these proteins and substances that determine how everything in your body works and how you will look.
In the early stages of an embryo, the ‘basic cells’ (totipotent stem cells) are not yet specialized and can still form any organ present in the body (as they all have the exact same DNA/cookbook), but once they are specialized, they can they don’t come back. The possibility to form a certain organ is therefore lost over time: if someone were to remove your liver, a new liver would not spontaneously grow back there.

Suppose, therefore, that science has the necessary techniques to transgender who wants to go from man to woman to remove the Y chromosome (man) and replace it with an X chromosome (woman), then the sexual organ will not be changed by this. The previous sentence also started with ‘couple’: it would really be a feat to adjust the DNA in a multicellular human being in every cell (trillions of cells, remember 😉 ) let alone remove part of the DNA . So they are far from that (although with her gene therapy baby Pia has now received an extra particle of DNA in a large part of her body cells for a long time that removes her disease symptoms).
And as you have just read: in the end it is not (directly) the DNA, but the substances such as hormones (testosterone, etc.) that will determine how you look. Adjusting the DNA will therefore not really help to give a woman masculine characteristics or vice versa. For this you need male (testosterone) or female (progesterone and estrogen) sex hormones that are mainly produced in the testes (testes) in men and the ovaries (ovaries) in women, respectively. Both testes and ovaries can only be formed in an embryonic phase, so that a transgender person will never be able to produce enough of the other sex hormone and hormone treatment will continue to be necessary.

So for a short and direct answer to your question: yes, a transgender retains his own DNA and starts looking like the opposite sex because of the hormones, not because of the DNA. On the other hand, the DNA in a person is (more or less) immutable: if someone starts to look different because of e.g. a hormone treatment, then you cannot see this in the DNA. The DNA is only the starting point of what someone can look like, the final result is determined by the addition of a whole lot of other factors, such as sex hormones.