https://www.ncbi.nlm.nih.gov/m/pubmed/28289563/

CONCLUSION AND RELEVANCE: Risk of PED was higher in men with longer exposure to 5?-RIs. Among young men, longer exposure to finasteride posed a greater risk of PED than all other assessed risk factors.

Comment: I have prescribed finasteride since it was first introduced. I have never had a patient with this condition reporting to me that their sexual side effects did not go away. I am having trouble reconciling this data from my own experience in private practice with well over 20,000 patients prescribed finasteride by me and the doctors working for me over two decades.