When female fertility is not normal, such as for a female partner over age 40 or if she is not having regular menstrual cycles, assisted reproduction with techniques like IUI or IVF are often necessary regardless of the sperm count or quality. In these settings, it’s best to have a female fertility evaluation first.  If the evaluation finds that natural conception is still possible with good chances, a vasectomy reversal could be considered. If assisted reproduction is going to be required anyway, the couple should consider a sperm retrieval by itself instead of a vasectomy reversal. There are two disadvantages of vasectomy reversal to consider: 1) having success but then finding out that assisted reproduction is still going to be necessary, and 2) failing the vasectomy reversal and not having had sperm extracted in case of a failure. Men who are at relatively high risk of failure are those whose vasectomies are over 20 years ago, those who are on testosterone or other anabolic steroids, and those with significant risk for abnormal sperm production such as men with obesity or other uncontrolled medical issues, alcoholics, or men who use cannabis regularly.