-three. I realize that I must
be getting old to think of you as young. Mary, you're thirty-seven. We
took a long time getting here. Fourteen years. We left an Earth that's
dying of radioactive poisoning, and we all got a mild dose of that. The
radiation we absorbed in space, little as it was, didn't help any. And
that sun up there--" again he nodded at the port--"isn't any help
either. Periodically it throws off some pretty damned funny stuff.

"Frankly, we're worried. We don't know whether or not we _can_ have
children. Or _normal_ children. We've got to find out. If our genes have
been bollixed up, we've got to find out why and how and get to work on
it immediately. It may be unpleasant. It may be heart-breaking. But
those who will come here in twenty years will have absorbed much more of
Earth's radioactivity than we did, and an equal amount of the space
stuff, and this sun will be waiting for them.... We'll have to know what
we can do for them."

"I'm not a walking laboratory, Doc," Mary said.

"I'm afraid you are, Mary. All of you are."

Mary set her lips and stared out the port.

"It's got to be done, Mary."

She didn't answer.

"It's going to be done."

"Choose someone else," she said.

"That's what they all say."

She said, "I guess this is one thing you doctors and psychologists
didn't figure on, Doc."

"Not at first," Farrel said. "But we've given it some thought."

MacGuire had installed the button convenient to Farrel's right hand,
just below the level of the desk-top. Farrel pressed it. Ralph and Mary
Pornsen slumped in their chairs. The door opened, and Doctor John J.
MacGuire and Ted Harris, the Exodus VII's chief psychologist, came in.

* * * * *

When it was over, and the after-play had been allowed to run its course,
Farrel told the Pornsens to go into the next room and shower. They came
back soon, looking refreshed. Farrel ordered them to get back into their
clothes. Under the power of the hypnotic drug which their chairs had
injected into them at the touch of the button, they did so. Then he told
them to sit down in the chairs again.

MacGuire and Harris had gathered up their equipment, piling it on top of
the operating table.

MacGuire smiled. "I'll bet that's the best-monitored, most hygienic sex
act ever committed. I think I've about got the space radiations effect
licked."

Farrel nodded. "If anything goes wrong, it certainly won't be our fault