Mention must be made of the 1:2000 girl babies born with TS. Again for reasons unclear, these children are born with an X chromosome either missing entirely or partially missing. Apart from many potential problems, they have non-functioning ovaries, which means no estrogen will ever be produced. So as the child approaches puberty, the lack of secondary sexual characteristics becomes apparent, no breast, thighs etc. develop. She is then given supplemental estrogen to correct this, but no progesterone to balance the estrogen. Unfortunately, under the misguided belief that estrogen prevents osteoporosis, (please refer to the page on osteoporosis), she is often put onto HRT. As TS was first reported as recently as the 1930's, it is possible that environmental poisons are to blame.
Combinations of antiretrovirals create multiple obstacles to HIV replication to keep the number of offspring low and reduce the possibility of a superior mutation. If a mutation that conveys resistance to one of the drugs being taken arises, the other drugs continue to suppress reproduction of that mutation. With rare exceptions, no individual antiretroviral drug has been demonstrated to suppress an HIV infection for long; these agents must be taken in combinations in order to have a lasting effect. As a result, the standard of care is to use combinations of antiretroviral drugs.  Combinations usually consist of three drugs from at least two different classes.  This three drug combination is commonly known as a triple cocktail.  Combinations of antiretrovirals are subject to positive and negative synergies , which limits the number of useful combinations.