We had the same issue. I noticed that sometimes when I changed his diaper, my sons "balls" looked bigger than other times. At first I thought it was just my imagination, but they kept changing size and I contacted our pediatrician. Turns out, his testies did drop but the tube they come down through (from abdomin to exterior) is supposed to close up on its own usually by around 18 month (at the latest). He had one tube that didn't close all the way so there was a flow of fluid going up and down which was making his balls look bigger at times. It didn't hurt him at all and the enlargement was only minor - nothing outragious! Our pediatrician recommended Dr. H. Gil Rustiton - he's a pediatric urologist with Childrens Hospital. She said if her son needed the same surgery, she'd go to him. I love and trust our pediatrician, so I went straight to him.
He was fantastic. Great bedside manor for both my son and us!! I checked him out, great resume as well. When my son was about 2 1/2 yrs, we went to Childrens Hosp and he had the surgery. The tube hadn't closed at all and due to the "wide open space" it was then considered a hernia. Anyway, they closed everything up and he completely recovered in no time.
Just keep the incision clean (easy to get infected if they're still in diapers), but otherwise, he did a fantastic job.
He had a Laurel office - I honestly don't know if he's still there. This all happened 4 years ago. Anyway: Laurel office: ###-###-#### or DC (at the hospital) ###-###-####.
Good luck!!
J.