I've read that a lot of research on genetics is done using twins, both identical and non identical. Since identical twins are genetic clones, studies have been done to see what is genetic, and what is due to outside or individual influences. One such study I read said that out of all the twins they had surveyed, all the identical twins had identical sexualities, whilst non identical twins could be the same sexuality, or different. I've often wondered how much influence genetics has over penis size, and how much is due to diet, exercise, stress, and other factors during puberty. Does anyone know if identical twin males have identical dicks? This also raises the question of bends and curves in the penis. Are they genetic, or due to how you wear your penis in boxers/briefs during the time its growing? Are there any identical twins on the site, or people with friends/relatives who are identical twins and know about this?