I have a 10 mth old son and I was wondering around what age should I expect his testicles to drop?

Before a boy is born, his testicles are located way back inside his belly. At about the 29th week of gestation, they slowly descend into the . In about four percent of baby boys, one testicle will be undescended – meaning it didn’t “drop” like the other one and is still in the pelvic cavity. The vast majority of undescended testicles will gradually drop into the normal position by the time the baby is a year old (in one-year-old boys, only 0.7% of testicles are undescended). If the testicle doesn’t ume the normal position by age one, it can be brought down surgically.