It seems apparent from your comments on the other answers that you aren't actually concerned about the network being "family friendly" or "safe for work" in the common sense of the terms. Rather, you simply don't like the idea of sexuality being discussed openly.
Others have expressed their opinion of that attitude, so I will refrain. But SE is not going to end a proposal or site simply because someone doesn't like its topic. I have friends with no interest in programming who participate in other sites on the network, yet they do not clamor for Stack Overflow to be closed. There are even people who reject advancements in technology that eliminate jobs and therefore oppose the creation of software, and they too would be ignored if they said SO should be closed.
It's your right to hold the opinions that you do. It is also your right to leave if you find Stack Exchange objectionable. It's even your right to express your opinion about SE. But the idea that a site should be closed because a minority does not think the topic should be discussed is ridiculous.
If you feel you cannot participate in something that has a separate area for the clinical discussion of sexuality, then I must (seriously and in all good faith) urge you to stop using the internet. The internet at large has no such clear dividing lines and if you have not stumbled across objectionable content yet, you will. And it will be much worse than the proposal.
family friendly
? I'm sorry, but our Stork is still under development. If the site is NSFW, don't go there while at work?