I have read quite a few threads that discuss where we get our penis size from; mom or dad or a combination of both. I belive that since the Y chromosone makes us male and that can only come from your father, then your sexual development can only be influenced by your father's genes. Everyone knows that if prostate cancer is common on your father's side of the family then you are more likely to get it. Is this because that particular trait is carried in the Y chromosones. For me and my brother and my cousins on my dad's side we are of average length but fairly thick. I remember when we were kids and stayed at my grandparents we used to all take baths together and no one stood out as smaller or bigger than the others. Even recently one of my cousins commented that he was remodeling his house and was considering installing a urinal in his bathroom so he didn't have to bend over the toilet in the morning to pee. Since we all knew what he was talking about I guess we all have erections that point straight out or up. Guys with erections that point down don't have that problem. I don't think that a mothers X chromosone carries any of her father's sexual characteristics since the Y chromosone is not present in her DNA. Girls can get similar traits of females on her father's side from the X chromosone that her father provided. It is also common knowledge that the Y chromosone is passed from father to son without changing. Meaning that your great, great, grandfather on your father's side Y chromosone is an exact duplicate of yours. Remember when they did genetic testing on the decendants of Thomas Jefferson's slave to determine if he had children with her and they acknowledged that all of the males had the exact same Y chromosone as Thomas Jefferson. But they also admitted that since Thomas Jefferson's brother also lived with him for a time it would be impossible to tell if he was the father or the uncle to the slaves children. So if the Y chromosone can be passed down for that many generations and even through different races without any change then that proves that the mother does not have an influence on her son's sexual characteristics. I'm not saying that if a man has a 9" dick his son will also have a 9" dick but you can be certain that his son will be above average.