From an evolutionary biological perspective, rape is seen as a mating strategy. Given the eventual extinction of Neanderthalensis, and the fact that physical attractiveness is also an important factor in modern mating practices of homo S, it makes more sense that the introduction of homo N. genes into homo S. population was less likely caused by sapiens being physically attracted to Neanderthals and more likel introduced through the sexual domination of sapien females by Neanderthal males. If that weren't the case the physical differences between the two species would have been less pronounced. That's my theory anyway.