There is a flaw in your logic. What you need to understand is that trans people have the brains of the gender with which they identify. There is increasing scientific and medical evidence that this is the case. Trans women are already women because they have the brains of women and think and act like them. It is our brains where our sense of identity lies and which inform our actions and attitudes. That is the reason that medical and surgical care was developed to treat those with gender dysphoria.
Being trans is not a mental illness. Being trans is not a choice. It is not a learned behavior, nor a social construct. No one can be converted from being trans to being a cis person. A cis person cannot be converted into being a trans person. It is a fundamental part of who we already are. We are a small but normal variant of a diverse human population. Depending on the statistics, between 0.6 and less than 2%. We are not defective anymore than someone who has diabetes or blue eyes or albino skin is. We are just a variant that sometimes occurs.
To focus strictly on external genitalia or the ability to bear children, is neither correct nor dispositive of the issue. Many cis women are born without the ability to have children for a variety of reasons from hormonal profile to malformed reproductive organs to infertility which cannot be medically treated. They are still women. Once you understand that trans women are already women regardless of external genitalia, you may come to understand this reality.
As to your argument that women, at least most of them, have the ability to bear children, this is not really the case. There are intersex people who look female and would be considered women. They have ambiguous genitalia. There are others who are hermaphroditic, having both male and female genitalia. There are women who are genetically men with XY chromosomes, but who do not process testosterone very well and develop as women. Some of them even successfully bear children. There are trans men who look like men, but who are fertile. Focusing on genitals may seem intuitively reasonable, but ignores the medical and biological reality of the wide diversity in the development of individuals.
In my own case, I have a female AR gene. I do not process testosterone very well. Prior to ever taking the first hormone, my estradiol was 122. The normal female range is 115-200. Men are less than 20. My testosterone was 100. Normal male range 300-900. Women, 18-96. My hormonal profile was androgynous at best, tending toward the female. The skeletal structure of my pelvis has both male and female characteristics. My hands and feet are dainty, very feminine. I have an ectomorphic body, tall and slender with wide hips and ample breasts, DD. I experimented once with lactation and reached the point of generating colostrum. I could have generated breast milk had I continued. Most of my life I was considered male. Today no one would think so. Undressed in a woman’s locker room, I don’t get a second glance. I look like any other girl. Not even my gynecologist can tell the difference. At my first appointment with her, she thought I was pregnant upon examining my vagina because of my hormonal profile. I had to assure I was not.
In wide gender and sex variations, humans are not alone. We see many examples in the animal kingdom. On a coral reef, clown fish are mostly male. When the dominant female dies, one of them switches sexes to become a female. Alligators develop as either male or female, depending upon the temperature of the eggs in the nest. There are many other examples. The problem is that your thinking is binary, but nature is not that way. All creatures including humans exist on a spectrum of possibilities, not one or the other. This is a common misconception which has nothing to do with the actual truth.
