[pbhjpbhj]

Sex [noun] absolutely plays a role in friendship. The intimacy of sexual relationship is a pertinent difference to a relationship the possibility of which changes the way people interact across the sexes. It may not be (as) pertinent to those who're bisexual/asexual/whatever.

You appear to intimate that if you were younger and unattached sex would pay a role, but that at odds with your 2nd sentence. Perhaps you could expand on your reasoning?