The only time women are not attracted to intelligent men is when they have the option of a good looking guy who is dumber than pants on fish. Still, it's comforting to know that given the choice of two ugly guys, women usually prefer the one who is not a moron. And obviously many women will still pick the guy who is both ugly and stupid if he has lots of money, good hair, is tall, or plays in a band. I did my own study to reach that conclusion. It's titled "Duh."
In my vast experience as an unattractive smart guy who was not always a syndicated cartoonist, there are in fact women who have fetishes for smart men. Not many, but they exist. My guess is that about 3% of the female public is in that group. That's probably good enough to keep the inventions flowing for a few more evolutionary steps.
The only risk to the future of humanity is that nerds will invent a technology that is better than sex with another human being. I'll try to keep this next part rated PG-13, so please be patient with the indirectness.
I assume some entrepreneur is already working on creating a business where guys will be able to buy a lifelike female body part that plugs into a standard USB port, and can be controlled by someone else across the Internet. That artificial body part could mimic a hand, mouth, or woo-woo. In the short run, the business model would involve paying women, in countries where such things are legal, to control the device and appear on a web cam chat. In the long run, artificial intelligence and CGI women will be controlling the action, so the whole system would only cost $100, with no recurring fees. And that will be the end of humanity because nerds will stop mating, their genes will die out, humanity will revert to the Bronze Age, and all the attractive, dumb people will be eaten by wild dogs.
I like to end on a positive note, so let's take a moment to be happy for the wild dogs.