The reason? He's a family man and a Catholic, and he's always made it clear that he won't do sex scenes. And ABC knew that.I'm not quite sure why, but I've never really liked explicit sex scenes in a legitimate narrative film. They have always given me this slight cringing feeling of "too much information." By "legitimate narrative film" I mean to exclude hard core pornography. That I actually don't mind at all.
Is this an unusual reaction? I really don't know for sure. I notice that, even in this age of anything goes, full frontal nudity is still rather rare in American movies. I'm told that it is much more common in European movies, but I would be willing to bet that most of the film industries in the world fall far short of the European in this respect.
W. C. Fields famously said "never work with children or animals." The obvious reason for that, I suppose, is that you never know what the damn things are going to do next. Another would be that, as long as you are on screen with a kid or a hippopotamus, the audience will not be looking at you. They will be looking at the kid or the hippo.
Sex, for human beings, especially in cultures that still have some standards of modesty in dress and behavior, is emotionally extremely powerful. If you put full frontal nudity on screen, you had better be sure that this person's pubic hair is the most important thing in the shot, because the audience will be unable to see anything else. Similarly, explicit eroticism is tremendously distracting from everything else.
In pornography there is of course nothing to be distracted from: no plot development, no characterization, no interesting dialogue, no symbolism, no subtle emotional cross-currents, etc., etc. Hence there it works completely differently. In fact, the material that would be so distracting is the very thing you are there to see.
Speaking of working with kids, take a look at this clip, from the British TV series, "Outnumbered":