So while this starts to answer your question with regard to mechanics and erection potential, it does not really get into the all-important emotional and psychological piece. I think that any time our bodies and our minds are not quite in alignment that there can be an emotional toll. This is in no way to say that all transgender people have emotional problems, but I just want to recognize that our bodies, our gender, and our sexuality can be confusing even when everything lines up. Having the added challenge of feeling uncomfortable with one’s physical sex can add some complications.
When measuring testosterone levels, it is critical to determine the levels of both free and total testosterone to understand the cause of any observed symptoms of deficiency (Khosla et al 2008).
Because of difficulties with equipment standardization and inter-laboratory variability, it is recommended that physicians consistently use the same local laboratories and gain familiarity with the accuracy, precision and definition of normal values for the assays offered in their communities (Morales et al 2010).
Genitals – Testes will lessen quite significantly in size. The production of testosterone and sperm is also greatly reduced. Penile size will also likely diminish. Sexual function will decrease, but the extent to which performance is affected is unpredictable. Erections may still continue, but will probably be less frequent, and not last as long, and in some cases may not be possible. Ejaculate will lessen, probably to the point of only producing a very small, clear discharge as a result of the prostate and the associated structures responsible for semen production being impeded. It is important to note, however, that the ability to orgasm is not dependent on either an erection, nor ejaculate. Anecdotally speaking, many transgender females report greater satisfaction with their orgasms after these changes occur in their genitals.