I agree that we should start HCG as soon as we start TRT. However, there are no studies at all published on this combination besides the one from Dr Lipshultz using 500 IU every other day of HCG to preserve fertility. I am meeting with his research team next week to look at a study design that better reflects what a lot of us are using now (300-500 IU twice per week). We should measure not only sperm count and quality but also testicular size and sex drive. A cross over design would be good (one group starts TRT alone, another TRT+HCG. Then after 2 months, those in group 1 add HCG and those in group 2 stop HCG for 1 month). This simple, non randomized, non placebo controlled open label pilot can give us enough answers to use it as a reference.