No significant scientific evidence has been documented to prove this, only patient claims. Sexual side effects can occur with age. My father said, when he turned 30, his penis just pretty much stopped working. No joke...not completely dead sex drive obviously, but the moral of the story is..... it just happens. My sex drive has been on a significant decline since I was 18, now im 25 and it just not he same as it was 7 years ago. Ive been on finasteride for 2 years( 1 yr, 10 months, 5 month break, now 2 weeks in again) and Ive havent really noticed a significant increase in the rate of decrease in any sexual functions(if this makes sense)... its been steadily declining over the past 10 years. However, There is the RARE case that someone could develope a severe reaction, but this occurs with all drugs.