If you only have one testicle, does that mean you won't grow as tall?
Your testicles produce both sperm and the hormones that cause your body to take on manly characteristics, such as wide shoulders, more muscles than a woman, and body hair. Each testicle has the capability of producing more of those hormones than you need, but various organs in your body monitor how much hormones are in your blood and then send signals to indicate that more or less is needed.
Since you only have one testicle, it simply means it is making up for the missing one by producing more hormones than would be usual in someone with two testicles that each share the load. So, no, having only one testicle does not mean you will end up being shorter. However, it does means you don't have a back-up. If you lose this last testicle you will probably have to take hormone replacements. Therefore, it is very important that you wear a cup during sports so that your last testicle isn't damaged.
Since the testicles also produce sperm, it means that you are only producing about 50,000 sperm a day instead of the typical 100,000 sperm a day most men produce. It also means that each ejaculation will contain less sperm in the semen. Since it only takes one sperm reaching the egg to conceive a baby, even at half-production you will still be able to have children. Most men are not considered technically infertile unless the amount of sperm in their ejaculations drop below 50,000.