Sex and the Single Sperm

Fake sperm almost sank Professor Todd Shackelford's career.

In the winter of 2001 at Florida Atlantic University, Shackelford and his graduate student Aaron Goetz were studying "sperm competition" in human beings — the notion that, just as other male animals try to spread their seed (and genes) widely in the evolutionary game of life, men and their sperm have developed ways over the past few million years to impregnate as many women as possible.

Although their research usually involved asking college students to fill out surveys about their sex lives, Shackelford and Goetz were also interested in a theory called "sperm displacement," and investigating it called for something a little more hands-on.

They wanted to know if men use their penises in a particular, thrusting way to displace potential rival sperm lurking in a woman's vagina. But studies with actual people having actual sex would be difficult to get permission for at a public university, so Shackelford's small staff in the psychology department quietly spent the first part of 2002 preparing an experiment that would model thrusting movements with an artificial penis and vagina and lots of simulated semen.

"Fake, you know — I made it with baking soda and some other nice things," Goetz says.

"There are recipes on the Internet, as you would imagine," Shackelford explains. The team planned to determine the best recipe via a ministudy, which they submitted to FAU's Institutional Review Board. "We would rate it for viscosity and if it felt real. It would be a blind situation. We had a couple of female graduate students and me and Aaron."

While waiting for the IRB's approval and thinking that a foreskin might make an especially effective sperm displacement tool, they also struggled to build an uncircumcised penis, which they planned to compare to penises without foreskins. "We know that penises in many cases appear designed to scoop out or grab sperm," Shackelford says. "In species of cats, for example, the penis has barbs and appears to be designed to scoop out semen placed there by a previous male. So it's not unreasonable. In human semen displacement, the foreskin might reach up and just grab hold of rival semen." But before they could construct a working foreskin, the team got a nasty surprise. FAU's IRB did not approve the proposal to test fake sperm.

Nathan Dean, then dean of FAU's College of Science, wrote Shackelford in February 2003 to deny him permission to test his fake semen. He had consulted two other faculty scientists who called Shackelford's work "highly speculative" and "poorly substantiated." In a memo to Shackelford, Dean wrote: "I would encourage you to explore more carefully the physiological basis of the work, in order to determine whether sperm competition in humans is a valid concept."

Shackelford says he felt shot straight through the heart. "What we got back was simply, 'This is pseudoscience,'" he says. "They were so offended by the notion that we were concocting simulated semen and had the wherewithal to say that we were going to rate it for how real it felt, they absolutely freaked out."

For 18 months, his work was on hold as he fought for the right to conduct his research. He produced a 600-page memo, packed with studies and articles, arguing that his life's work wasn't pseudoscience. Eventually, he abandoned the artificial semen and the functional foreskin entirely.

Five years later, Dean Dean has been replaced and Shackelford is tenured and is being considered for a full professorship. He is considered a rising star in the field of evolutionary psychology, and FAU, eager to get national attention, has apparently forgotten that it had any previous doubts about the legitimacy of his work.

Now Shackelford is steadily building his case, using state and federal money, to prove that jealousy, deep thrusts during sex, and even rape are all male behaviors that are biologically programmed by evolution so that men can pass on their genes to as many offspring as possible. And though few outside the growing and controversial field of evolutionary psychology seem aware of it, the professor is poised to make FAU a center of some of the most contentious science in the world.

As Aaron Goetz explains sperm competition to a room full of fellow scientists and students at FAU, the 27-year-old looks more like an actor playing a graduate student than the real deal. A dusting of stubble and slightly unruly hair softens his aquiline face as he talks casually about ejaculation and sperm motility while covering a blackboard with chalk drawings of sperm cells until there's no room for anything else.

In the front row, his mentor, 35-year-old Shackelford, fidgets as he watches his protégé through small, round-framed glasses and over a clipped beard.