Despite what you may tell yourself, your penis is not like a fine wine, meaning it's not getting better with age.

You've heard about all the biochemical issues. As your testosterone level droops, it takes more and more to arouse you, and longer still to both attain an erection and subsequently have an orgasm. The volume of your semen declines. Your fertility – the measure of your semen's potency – also takes a nosedive as you get older. There is also a gradual decline in your urinary function, with a much weaker stream as a result of weakened bladder muscles and sometimes prostate enlargement.

But we're not talking about performance and potency here, we're talking about Mr. Happy himself. What physical changes to your penis can you expect as you grow older?

Let's start with your number one worry: size. Sorry to confirm your worst nightmare, but your penis will shrink as you age. In both length and thickness, your shaft will irreversibly diminish. It's not a lot, but you'll notice. If your erect penis clocked in at 6 inches when you were in your 30s, you'll be staring down at around 5 to 5-and-a-half inches sometime by your 60s or 70s.

As goes Mr. Happy, so go The Boys. Your testicles will begin to shrink around age 40. A 30-year-old man with 3 centimeter diameter testicles can expect 2 centimeter testicles by age 60.

You may find yourself being more concerned about the perception of a smaller penis. As fat accumulates on your abdomen, it can make your penis appear smaller – in obese individuals, abdominal fat may all but bury the penis. Fortunately this is some shrinkage you can reverse – by hitting the gym and watching what you eat.

The science behind your diminishing returns can be found in the plaques that build inside penile arteries as you get older and impede blood flow there. Collagen also builds up over time in the stretchy fibrous sheath that surrounds the erection chambers. These arterial blockages chamber stiffenings both result in smaller erections.

As you age, the head of your penis will lose its purplish coloring as a result of the reduced flow of blood there. You will also see a loss of pubic hair as your testosterone wanes, as well. Eventually, your penis will gradually revert to its prepubescent mostly hairless condition.

Your penis will also grow less sensitive as you age. This can effect your ability to achieve and maintain an erection.

But don't let any of this weigh too heavily upon your shoulders. None of these changes need affect your sexual satisfaction in any way.

Sources: WebMD