Dear,
Welcome to HCM
We understand your concerns
I went through your details. I do not think you have to worry about your child's penis size. Your child is 10 years. In the initial years, it is quite natural that the ratio between penis size and testicle size is non-comparable. Testicles size is always bigger.
Upto the age of around 12 years, or till the child reaches fully
puberty, the penis size will never be more than 3 inches, at the maximum. But after that, there could be a drastic growth in the length and the penis can grow upto 6 inches. Therefore, as of now, the penis size is reasonable. There is no significant symptoms to worry about
testosterone levels.
If you require more of my help in this aspect, please use this URL. http://goo.gl/aYW2pR. Make sure that you include every minute detail possible.
Hope this answers your query. Further clarifications are welcome.
Good luck. Happy New Year. Take care.