In case you hadn't noticed, it's National PornSunday! It's a strange event promoted by a couple of Christian ministers who seem to be disturbed by the "secret shame" of Christians who look at pornography, and are making a big noise about it. (I rather cynically suspect that they've discovered that sermons about pornography are a great way to pack the pews.) They cite some statistics that I presume are supposed to be shocking:

• Number of pornographic web sites: 4.2 Million
• People who regularly visit Internet porn web sites daily: 40 million
• Christians who said pornography is a major problem in the home: 47%
• Breakdown of male/female visitors to pornography sites: 65% male - 35% female
• 30% of unsolicited e-mails contain pornographic materials
• Women, far more than men, are likely to act out their behaviors in real life, such as having multiple partners, casual sex, or affairs.
• Porn revenue is larger than the combined revenues of all professional football, baseball and basketball franchises.
• US porn revenue exceeds the combined revenues of ABC, CBS, and NBC at $6.2 billion.

I can't vouch for those statistics, and they don't give their sources. There are some interesting contradictions there: if 47% of Christians claim pornography is a "major problem", doesn't that suggest that the figure of 40 million daily porn viewers is an underestimate? It's also not clear exactly what they propose to do about it, and they are simply implicitly assuming that there is a problem here.

If we assume their numbers are somewhat accurate, though, what is that problem? What they tell us is that people like sex. This is not a surprise. We're fascinated by sex, we're curious about our bodies, and we also have curious monkey-minds that are attracted to the forbidden. When I see that pornography is such a huge industry, and given that it doesn't and shouldn't harm the viewer, I think the proper response is to embrace it, not tell people they should shun it or feel guilty or take action to shut it down. Why not be open about it, and work to alleviate genuine problems within the industry, like the exploitation of women, its potential as vehicle for sexual harassment, and the psychological problems of viewers who are obsessive about it?

Personally, I don't find pornography that stimulating, and am not particularly interested in promoting it…but I do think it would be good for society if we did have a healthier, less guilt-filled attitude towards perfectly normal physical functions. For one thing, more open-mindedness about sex and reproduction might make pathological stories of parental abuse of their teenagers rarer. Instead of a day where we try to make people feel wrong about their normal interest in sex, I think we should make this a day where we feel good about it—a National HealthySexDay!

In the spirit of subverting PornSunday, here is a QuickTime movie of copulating zebrafish (730K), made by a couple of students in my lab, Matt Enke and Jason Ward. It's very short—only about 2 seconds long—but that's because I've cut out all the foreplay. The fish spend around 20 minutes nuzzling and chasing each other, and engaging in various displays that I'm sure the fish find very stimulating, but are rather cryptic to my mammalian eyes.

You may find everything about fish behavior utterly cryptic, so here are a few annotated frames from the short movie to help you puzzle out what's going on. Download the movie and follow along! Single-stepping through the frames will make it easier—otherwise, it's going to look like the fastest boink you've ever seen, and if you blink you'll miss all the fun.

The mating male and female start out swimming closely with one another, rising up towards the middle of the tank.

The loving pair swim in a tight pas de deux.

Suddenly, the two twist and swing their pelvic fins together. Notice the third fish following along attentively.

Money shot! The little arrows point to a few of the cloud of eggs that suddenly spurt out; the male also ejaculates simultaneously. The third fish's attentions turn to the eggs.

The female has jetted away quickly, while the male follows. Note the kinky, hungry female pointed to by the red arrow; she has risen up into the cloud of eggs and sperm and is about to suck one down.

Wasn't that beautiful and fun? I suspect my fish are also happier and better adjusted than any gang of repressed Puritans you can find.

If you'd like to see this sort of thing going on in your house, I'll mention that healthy, well-fed zebrafish, Danio rerio, are routinely frisky. Their sexual behavior is on a circadian rhythm, and they respond to dawn's light with regular orgies, every day. It's easy to stimulate—get up early and turn the light on in your aquarium—and it's easy to spot, with very excited fish darting about and tangling up in wild slippery balls of roiling sexual activity.

It's also a good marker. When my fish stop having sex every day, I know that they are feeling stressed or ill or exhausted or aren't getting their proper nutrition. And when I see people afflicted with repressive Christianity that turns sex into a shameful activity, I can't help but make the comparison with a disease.