Your penis is the most important part of your body.
Therefore, society as a whole benefits when everyones penis is happy.
But, when going for an interview and someone in HR asks what you majored in and you tell them Penis, that might be kind of funny.
Me, I bought my first Harley when I was 19 and I think I majored in Penis for quite a few years. It was a study on how my Harley was directly proportional to Mr. Happy being happy.
Girls got to know that if they wanted a ride on the Harley, Mr. Happy had to approve.