Hello, It is a shame that your physicians do not seem to be able to adequately explain to you why you do not menstruate. It is possible, through a combination of diagnostic tests (hormone levels, diagnostic studies such as an MRI of your brain, and an ultrasound to evaluate the organs of your pelvis) to obtain an accurate diagnosis. In order to develop sexually and menstruate normally woman or girl must have five organs of the body that develop normally and function properly; it includes the hypothalamus of the brain, the pituitary gland, which is located below your brainstem, and then your reproductive organs themselves: your uterus, vagina, and ovaries. Abnormalities of function in any of these organs can prevent a woman from being able to menstruate. If you developed normally as a young girl, meaning that you grew breasts, underarm hair, and pubic hair without taking hormones suggest that your brain tumor was not the cause of your inability to menstruate. Furthermore, if your pituitary gland were the source of the problem, you most likely would ve needed other types of medication to treat other hormonal abnormalities, such as your thyroid function, during childhood as well. So at this point, if you have never menstruated, there is a possibility that you may have an abnormality of your ovaries, or even your uterus or vagina. Imaging studies such as an MRI or even ultrasound of your pelvis can make sure that you have all your required reproductive organs and they are connected to each other properly. Some women may be born without a uterus, or with a blockage between the uterus and the outside of the vagina which prevents menstrual flow from leaving the body. Another way that it can be tested if your reproductive organs work is to give you some hormonal medication, like birth control pills, which will make a woman have regular periods as long as she has a functioning uterus and vagina. If they were, it means that you have all the required parts for menstruation and that it is a hormonal problem. A specialist called a reproductive endocrinologist is a kind of gynecologist doctor who specifically studies hormones, both to help women achieve pregnancy as well is treat other hormonal health conditions of women. I strongly suggest that you consult with a specialist in this area as I truly believe that that type of specialist should be able to get you the information that you need and help you conceive if it is physically possible for you. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Jacqueline Brown