To decrease the birth rate would require a big decrease in sexual activity. Here are the numbers: Researchers followed 881 couples through 7,017 menstrual cycles, with two stipulations for the volunteers: sex just once per month and no birth control of any sort. They found that on days outside the fertile window, conception occurred about 5 percent of the time, while during the fertile time around ovulation, the rate was 25 percent. Call the overall rate about 10 percent per unprotected intercourse. But protection with condoms or the pill or whatever brings the number way down—let’s say that rather than 10 percent, the rate with protection is 1 percent. That means to prevent one pregnancy an American would have to have sex 100 times less per year, just about a year’s worth of activity.

Are we having less sex? What’s behind the drop in the U.S. birth rate!? (via newsweek)

Sex: It’s a good thing | Science Codex

Sure, sex may be fun, but it’s a lot of work, and the payoff is by no means certain. Scientists have speculated for a long time on why all living things don’t simply make like amoebas and split. Now a biologist at Michigan Technological University has found one good reason: sexual reproduction strengthens an organism’s ability to adapt; specifically, it may lead to stronger disease resistance. Erika Hersch-Green tested the idea on 32 different species of evening primroses. These native North American wildflowers are unusual in that a number of species reproduce asexually, essentially through cloning themselves. That allowed Hersch-Green and her colleagues to compare 16 species that reproduce sexually with an equal number that function asexually. “We found that the sexual plants have an increased ability for adaptive, positive evolution,” she said. “That’s in line with many of the theories of evolution of sex.” Scientists believe that sexual reproduction offers two big advantages: It can sweep bad mutations out of the gene pool more quickly. Also, by shuffling parents’ genetic material each generation, it increases the likelihood that new genetic combinations will arise that help organisms adapt to their environment.

Sex: It’s a good thing | Science Codex

In the next five years or so it will be possible to build lifelike robots. These robots will look, move, and feel like fellow humans — but, unless the technological singularity comes early, these robots won’t be excellent conversationalists. According some recent research, though, they will make fantastic prostitutes. If you’ve ever read a sci-fi novel or spent a little time thinking about the future, the concept of having sex with a robot probably doesn’t surprise you — I mean, it’s going to happen eventually, right? If you’re like me, though, you probably thought about having sex with a cyborg, an intelligent robot that is convincingly human — something like that hot blonde from Battlestar Galactica (pictured above), or Data from Star Trek — not some dumb sexbot. (via Do humans dream of android prostitutes? | ExtremeTech)

Let’s cut to the chase. Would you pay to have sex with a robot prostitute? Ian Yeoman and Michelle Mars think someone will. Yeoman is a futurist with an interest in tourism, and Mars is a sexologist at the University of Wellington’s Victoria Management School in New Zealand. The duo just co-authored a paper entitled “Robots, Men and Sex Tourism” for the current issue of Futures. (via Robot Prostitutes, the Future of Sex Tourism : Discovery News)