Platonic friendship: possible or not?

Since I started to come more regularly to Portugal, I started to notice how easy and natural male-female friendships seem here. A recent research performed by the University of Wisconsin (400 men and women participated) found however that men tend to be sexually attracted to their female friends more often than the other way around. And this could get in the way of their friendship. A Dutch research performed by 'Psychologie Magazine' (5000 participants) showed the same results.
I wonder: is my impression of Portuguese mixed friendships based on reality? Are there cultural differences?