Sperm: The Final Frontier

In June 2004, Tash's fax machine began spitting out spreadsheets from the NIH. Tash saw only zeros. None of the rats had produced a litter. Every few weeks, Tash would get new faxes. More zeros.

Three years later, Tash recalls no adrenaline rush during this drawn-out moment of discovery. No congratulatory phone call from the National Institutes of Health. No lighting of a rare cigar. Just faxes with zeros.

"It was like, 'Wow," he says calmly. "We knew it was potent." It's a cold spring evening on the first dry, clear day after an awful winter. At Settlers Acres Stables in Greenwood, Tash wears a black helmet, a black sweater, black riding pants, black boots and gloves.

This is one of Tash's favorite places. About 45 minutes east of his office, past Lee's Summit, the city fades away and the air begins to smell like cut grass, clean mud and sweet manure.

Tash's horse is Jabberwocky — named by his breeder because the horse's attitude reminded him of the Lewis Carroll nonsense poem. "The look in his eye is a combination of love and impishness," Tash says. He calls the horse Jabber for short. Gray with brown speckles that will fade to white in the next year or so, Jabber is a 7-year-old Lippizan — the most elite breed of horse.

In the center of the ring are fake stone walls and trick hurdles. Three other riders are practicing with a trainer. In the crisp air, their voices seem far away.

"The first thing I gotta do is walk him around, take the sightseeing tour, make sure everything's as it should be," Tash says from his place in Jabber's black saddle. He notes that a horse's eyes are on the sides of his head, not in front. They walk around the ring in one direction, then in the other, so Jabber can survey his surroundings from each eye.

After a dozen or so times around, Jabber picks up the pace from a walk to a trot. Later, Tash and the horse will speed up to a canter. The point of their training is for Jabber to understand Tash's commands solely from the movements of his leg or seat, not from any pressure in the reins.

When they stop and stand perfectly still, Tash's face is dripping with sweat.

It looks as if they've just been riding in circles, Jabber's footsteps a steady pish-pish-pish in the arena's pea gravel, but they're training hard. They will likely ride in dressage competitions four or five times between now and October.

"With a young horse like this, it's a constant conversation," Tash says after another few times around. "The whole idea is for the horse and rider to work together as a team, the rider with as little effort as possible and the horse with as much willingness."

Ever since his Cambridge days, when he competed on the equestrian team, Tash has wanted a horse with which he could do classic dressage. His son, Matt, who is now 26, and his daughter, Rose, 27, grew up riding.

"Winning the ribbons used to be the goal," he says. Now, however, he just works on getting better.

That change in attitude parallels the way he has thought about his research over the years. "Now my goal is progress, not perfection," he says. "Each goal is a stepping stone to the next."

Mostly, though, he rides for the beauty of it. Their training becomes a meditation. "You have this 1,100- or 1,200-pound being that you're working with that requires your total attention," Tash says. "It's a way to focus on something outside of work."

Which is probably a good thing. Because back at the med center, Tash's work recently got a lot more intense. The patent for their original chemical compound — now renamed Gamendazole — is pending. Going back to the analogy about the mother dog and her puppies, Tash says the drug cuts off the mother's milk supply (the Sertoli cell) where the most mature puppies (sperm) are suckling. Without any milk, they stop suckling, but they're not mature enough to survive on their own.

In March, KU Medical Center announced that the NIH had given Tash $9.5 million to lead a new Interdisciplinary Center for Male Contraceptive Research and Drug Development. Georg, who left Lawrence last year and now heads the department of medicinal chemistry at the University of Minnesota's College of Pharmacy, is associate director. Out of a new administrative office on the same floor as Tash's lab, they'll work with researchers at seven universities, including Duke University and the University of California-San Francisco.

"It's nice to be part of this elite group," Tash says of his colleagues at KU. "We're among the big boys."