If the testicles are undescended, they are "there" they are just in the wrong place. They are probably still producing hormones that are making him mark. From what I understand, the testicles are somewhere "up there" and need to be surgically removed. There are a couple problems that can occur from leaving them. Testicular cancer is one. I would get this taken care of right away and then see if the problem with marking resolves. Good luck!!!
Here is a short article from Drs. Foster & Smith that explains it:
http://www.peteducation.com/article.cfm?cls=2&articleid=897
Here is a short article from Drs. Foster & Smith that explains it:
http://www.peteducation.com/article.cfm?cls=2&articleid=897