There are other conditions too that need to be looked for. One is what I have, buried penis. This condition means that there is a great deal of excess fat pad overhang caused by the penis being permanently pulled back against the pubic bone and thus shortening it. If you palpate my penis, you can feel a lot of it is inside the inguinal canal and scrotum. Weight loss or gain doesn't change the situation either as the retractile ligaments keep pulling the penis in as far as it can go. So you look like you're tiny even when you're very thin.
This condition, and others related to it such as trapped penis (due to radical circumcision) are not uncommon and surgery to correct it is simple in prepubertal children. It's easy to diagnose too. All a doctor need do is ask the boy to stretch his penis out as far as it can go. Flaccid stretched size is close enough to erect size to give a doctor an idea of what's going on. But most doctors won't even look for this if a parent doesn't mention anything. My pediatrician never bothered to look despite the fact my flaccid length was less than two inches and my flaccid girth was the same. I assume he assumed I would grow out of it at some point.
Buried penis is reported rarely in adults but that's because most urologists figure that it's underdiagnosed. I had seen a few urologists before, but it took one of the top guys in the country to take one look at me, feel around a bit, and discover what was going on. Corrective surgery is a bit involved, and expensive, but is covered under insurance if the condition interferes with normal functioning, which mine does. I was actually looking to get the surgery too just before I was diagnosed with cancer, but the cancer has to be addressed first and surgery now is not a good idea. Corrective surgery will allow me to have a normal flaccid penis and allow my penis to erect to its full length without much of it being hidden underneath my fat pad and in the scrotum and thus allow more penetration. Urination will be much easier too.
Things like buried penis and its related conditions should be checked for any time a doctor or parent even remotely suspects it's an issue. It's really simple to check for and correct before puberty. It can even be done after puberty. I wish I had known earlier what was going on. Would have saved me a world of heartache.