I'd monitor it if I were a father, but I wouldn't watch over my kid's shoulder. If the boy or girl had questions, I'd answer them, but I wouldn't steer them in any way nor would I condone that which they look at, as long as it's legal amongst adults.
Besides, why condone sex when cartoons like GI Joe, Dragonball Z, the transformers, etc., all contain violence to a certain degree. We've all watched certain series or movies like Rambo, predator and tour of duty, which contained a lot of violence as well. If I had to choose, I'd prefer to see my child watch "no man's land X" or "Robinson Crusoë on sin island" any time.
Besides (again), kids already have access to porn/softporn whenever they want. Just buy a comic of the X-men for instance. All that's missing on the female bodies is nipples shining through the suits and camel toes. Any kid with a bit of fantasy can use that to fulfill it's needs as well, and adults would be unaware of what was going on in their child's mind.