There are a number of different factors that determine your penis size. Of course, you can use the Quick Extender Pro to change that by permanently adding inches to your erection. However, 
before you start using the device, genetics and age worked together to decide what your natural penis size would be.
Recently, scientists have discovered that the hormone androgen can actually determine your penis length when you’re in the womb. The more of this hormone that is present during a certain stage of pregnancy (eight to twelve weeks), the larger the penis will be. However, there is no indication that taking this hormone later in life has any effect on penis size at all. In fact, it may actually be harmful to your health.
Genetics will also come into play. As long as the amount of androgen is normal, your penis size will be determined by the DNA you received from both your mother and father. This doesn’t mean your penis will be the same size as your father’s or any of your brother’s penises. Every sperm is different.
Age is another consideration. While teenage boys are often concerned with their size, few know that their penis is not done growing until they’re in their twenties! In fact, some men do not reach their full size until they reach age 30 or so. It’s different for every man, so even if you’re in your twenties and think you’re too small, you may not be done growing yet.
Of course, don’t let that stop you from giving genetics a hand! The Quick Extender Pro naturally adds inches to your penis, so it won’t do anything to get in the way of your body’s own growth. In fact, it will help it along by persuading the body to add more cells to your shaft, thus permanently increasing your length.