I have a 6 year old son and I've noticed that his testicles have dropped and hang. He's my only son and I don't know if this is normal.
It is known as precocious puberty. It means that puberty is happening sooner than it should. For boys puberty (the rising of testosterone in the blood) shouldn't start before 8 and that leads to first external signs of puberty happening a year later. The average for the first external signs of puberty is 11. If his testicles are swelling and hanging, then his testosterone has risen at least a year ago, which is way too early. He needs to be examined by a doctor to find out why it started so early. See Mayo Clinic's article on Precocious Puberty.
Generally the treatment is to give him medication to slow down his development.
Thank you for the reply. I appreciate the advice. He is due for a physical this month. I'll speak to my doctor about it. Thanks.