What differences are there for men who have one testicle as compared to a normal man?

Men with only one testical are just as fucntional sexually as other men. The major difference is the appearance - although a prostetic peice can be inserted for looks - and the ability to produce sperm. Men with only one testical have a greatly reduced sperm count and may find it difficult to have a child naturally. You may be required to go through invetro procedures to have a child.