Yes, I agree. Have you discussed this with his pediatrician? Likely it is going to be just fine.
Hello and welcome. Thanks for your question. Most likely your son has regular annual check ups with his doctor. At this time, they should perform a brief check of his genitals which is just visual. I would ask at that time. It doesn't appear you are asking about testicles that haven't ascended into the scrotum. https://www.webmd.com/parenting/baby/what-is-an-undescended-testicle#1. This is not your concern, correct? That again is normally addressed if the testicles do not drop on their own younger than the age of your son. That a doctor hasn't commented on this would be a good sign that he is actually normal and developing at his own rate. But do follow up with your doctor at his next well visit.