Any size can do it as long as you know what to do. Women don't orgasm due to the size.
common factors are genes make sure you eat right and be sure you exercise alot
No it is not. It is how you use it that counts most. There are different positions that you can use depending on your size.
Well... you ever heard of size doesnt matter? it sorta does though, having something too small or too big is kinda bad, but all you need to do is compensate for it. Foreplay, stuff like that -google...
Over 7 inches if you are over 18 years old and if yours is under 6 inches well... you are screwed my friend