You've all over looked the American rating system for movies. Here's how it works:

G-Fully clothed, a lingering kiss with a slow fade to the next morning
PG-Mostly clothed, a big slobbery kiss in bed and a slow fade to morning.
R- The bra comes off, butt cheeks in view, the kiss starts on the lips and slides down to at least the navel. No fade to anywhere.
X-Full frontal nudity and simulated intercourse but no bodily fluids. No fade.
XXX-Nudity but may include high heels and such. Detailed close-ups of the proceeding, bodily fluids and all, endlessly in the most contrived situations and positions you can imagine.

And then there's the Discovery Channel for the whole family where they drive a fiberoptic camera up the vagina and we all observe the miracle of conception and just about all that may entail.

The more you look the more you see.