The problem with these first two creatures was that their being genetically half-human compromised their legal status. The project’s legal officer had rendered an opinion that a court would be likely to decide that they were, indeed, human beings. Worse, though, they had human personalities and could fight through programming they did not like.

But they were teenagers, Mark and Gina, full of life and joy and excitement, in school, crazy about each other, totally unaware of what they really were. He could maybe do what he had been ordered to do to generation three, but not to them, they were the children his own unfortunate genetics had prevented him from having.

He loved his kids, and frankly he even loved generation three. How could you not love Gamma’s caring bedside manner, or Alpha’s quiet expertise and officer’s insightful wisdom—or even the wonderful, ferocious loyalty of the four pure soldiers?

The triumph of generation three was that they fulfilled all ten criteria, including the most important one, that they were absolutely in no way classifiable as human. They weren’t animals, either. Because their crucial brain regions were populated not by neurons but by artificial memristors, they were, legally, machines.

Their essentially reptilian biology enabled them to regrow organs and limbs, gave them enormous strength, and only enough sensation to warn them of potentially fatal wounds. They could jump four hundred feet. They could move at least as fast as generations one and two. Their intelligence, while less supple and imaginative than that of the first two prototypes, was functionally superb.

Their eyesight was a signal achievement. He had managed, as long as microwave tuning was used to excite artificial rods and cones in their retinas, to give them vision better than that of eagles. The downside of this was, unless the microwave field was turned on, their vision was as limited as that of a lizard. One of his ambitions for generation four was to actually use eagle eyes, but that would be complex and would change the size of the orbits considerably. Theoretically, generation three could be fitted with human eyes, but he had not been willing to try this, largely because obtaining eyeballs outside of normal medical channels was going to carry unacceptable security risks. They also had the temperature sensitive sight of snakes, which gave them something of a backup.

In all, they had just a smattering of human genes, under 2 percent, which were mostly involved with the skeletal structure. And those, using the extraordinary technology he had gained from the aliens at Dulce, could now be synthesized and the bones strengthened with embedded carbon-fiber strands. Generation four would contain no human genes at all.

An inevitable side effect of all the modification, however, was that generation three did not appear human, and generation four would appear even less so.

Of course, now there would be no generation four.