Hi I understand your concern. The right testicle is undescended and seems to be in your groin which is the most common position for an undescended testicle to be. In that position it is more prone for injuries as well as the testicle becomes smaller slowly as you grow older. Hence I would advice surgery for it. In the first instance I would recommend an ultrasound to assess the size and nature of the testicle and if looking satisfactory, then it can be brought down by a simple operation in the groin. One testis is enough to maintain fertility and erections as long as it is healthy. Even if sperm production is low from the undescended testicle, it is worth retaining it in order to maintain the testosterone production.