yes and no.
its very rare for any relationship to be STRICTLY platonic once you dig deep enough. i know this will be argued but its true. most people are sexually attracted to each other, just alot of the times its not noticeable and up on the surface.
and you have to take into account the difference between platonic, sexual, and romantic attraction.
i think the question isnt really about the sex aspect, but the romantic.
of course any two people can be friends and never become romanticly attracted to eachother. but seldom can they resist sexual attraction, even if were just talking sub conscious. frued would even say we are sexuallly attracted to our own parents. tho its a bit of a stretch.