Speaking from the Gay side of my B-sexuality, I would say that size certainly doesn't count - at least not as far as minimalistic sizes go. Larger ones are another matter. The bigger they are (girthwise, anyway), the more difficult & more painful they are to penetrate. I once had some really satisfying sex with a guy with a micro-penis (less than 2" erect), which didn't seem to have developed any since puberty. There was no problem with Mutual Masturbation & Oral, and although he was physically unable to manage Anal penetration, the size of his penis made no difference when it came for me to penetrate him. I can, however, appreciate how this condition would be a problem for the ladies, without the use of a strap-on penis extender.
