So long as the question is written with a reasonable level of maturity and lack of vulgarity,
No. Absolutely not.
Generally speaking, the Internet is a PG-Rated environment - on a good day. The most innocuous search will bring you results that would leave an average person silently sobbing and rocking themselves in the corner. If you have children that you're that concerned with reading about the possibility of characters having sex, you need to be more actively monitoring/guiding their surfing.
From the Stack Exchange Terms of Service (note that "Subscriber" is defined earlier as a synonym of "Subscriber" or "You"):
Subscriber certifies to Stack Exchange that Subscriber is an individual (i.e., not a corporate entity) at least 13 years of age. No one under the age of 13 may provide any personal information to or on Stack Exchange (including, for example, a name, address, telephone number or email address). Subscriber also certifies that they are legally permitted to use the Services and access the Network, and takes full responsibility for the selection and use of the Services and access of the Network.
So, technically, those young'ins shouldn't be surfing StackExchange by themselves anyways (Yes, I know that's unrealistic - but they're the ones technically breaking the rules here - not us).
We've had other questions in the past about characters having sex. Human-Human, Human-Alien, Android-Human, Possessed-Human, Vampire-Human, the list goes on.
Some examples which would be blanketly closed by this change:
Also check out the sexuality tag.
Based on all existing rules, they appear to be on-topic. They are about sci-fi/fantasy; They are reasonably scoped; They are not open-ended/list questions; They are not subjective or encouraging discussion; They are written reasonably maturely and avoid vulgarities and obscenities.
I hate using the slippery-slope argument - but it really is an important subject. What other questions are we going to have to start banning to "protect the children"? Anything discussing violence? Anything discussing religion? Anything discussing evolution? Anything discussing witchcraft or demons?
Simply saying "adult content" is way too vague, and nobody is stepping up to offer any sort of definition of what that should include.
I'm not disagreeing that the question is kind of tasteless. But it's a valid question about a valid topic, and it's written with a acceptable level of maturity. Unless these questions cross the line of common decency, they should remain open.
Allowing adult only content would, in my opinion, open a floodgate for the users who game the system for reputation as there is an endless supply of dreadful adult questions.
This is demonstrably false. Searching questions for...
- Sex: 36 results
- Sexual: 32 results (the search engine does not seem to do partial searches correctly)
- Intimate: 15 results
Many of these could not even be considered "adult" - others definitely could, but they mention one of those keywords. Even if we count these as all being unique (they're not, there's a bit of overlap), that's a total of 83 questions out of 9800 existing questions at this moment. That's .8% of the questions. Even if we widen our search parameters within reason, we're still not going to hit anything remotely concerning.
Despite the existence and non-closure of many of these questions, there has been no flood of users trying to game the system for reputation.