"When I picked the property for Maison Long, I made sure that it included space for a growing family, that's all, since they had three bucking and one in the chute the night we planned it. Rearranging hours gave them privacy from each other, too. Happy as it is to snuggle and make love, nevertheless, when you are really tired, it is often good to have the bed to yourself-and the new routine not only allowed this but necessitated it, part of each day, through staggering their working hours.

"But I also planned room to give them privacy from their children-and to cope with another problem Llita did not have straight and Joe may not have thought about. Minerva, can you define 'incest'?"

The computer replied, "'Incest' is a legal term, not a biological one. It designates sexual union between persons forbidden by law to marry. The act itself is forbidden; whether such union results in progeny is irrelevant. The prohibitions vary widely among cultures and are usually, but not always, based on degrees of consanguinity."

"Y'r durn tootin' it's 'not always.' There are cultures which permit first cousins to marry-genetically risky-but forbid a man to marry his brother's widow, which involves no more risk than it did for the first union. When I was a youngster, you could find one rule in one state, then cross an invisible line and find exactly opposite laws fifty feet away. Or some times and places both unions might be mandatory. Or forbidden. Endless rules, endless definitions for incest, and rarely any logic to them. Minerva, so far as I recall, the Howard Families are the first group in history to reject the legalistic approach and to define 'incest' solely in terms of genetic hazard."

"That accords with the records in me," Minerva agreed. "A Howard geneticist might advise against a union between two persons with no known common ancestry but place no objection to marriage of siblings. In each case analysis of genetic charts would control."

"Yeah, sure. Now let's drop genetics and talk about taboo. The incest taboo, although it can be anything, most commonly means sisters and brothers, parents and offspring. Llita and Joe were a unique case, brother and sister by cultural rules, totally unrelated by genetic rules-or at least no more so than two strangers.

"Now comes a second-generation problem. Since Landfall had this taboo against union between siblings, I had impressed on Llita and Joe that they must never let anyone know that they thought of each other as 'brother' and 'sister.'

"Fine so far as it went. They did as I told them, and there was never a lifted eyebrow. Now comes the night we planned Maison Long-and my godson is thirteen and interested, and his sister is eleven and beginning to be interesting. Full siblings-both genetically hazardous and contrary to taboo. Anyone who has raised puppies-or a number of children-knows that a boy can get as horny over his sister as over the girl down the street, and his sister is often more accessible.

"And little Libby was a redheaded pixie so endearingly sexy at eleven that even I could feel it. Soon she was going to have every buck in the pasture pawing the ground and snorting.

"If a man pushes a rock, can he ignore an avalanche that follows? Fourteen years earlier I had manumitted two slaves- because a chastity girdle on one of them offended my concept of human dignity. Must I find some way to put a chastity girdle on that slave's daughter? Around we go in circles! What was my responsibility, Minerva? I pushed the first rock."

"Lazarus, I am a machine."

"Humph! Meaning that human concepts of moral responsibility are not machine concepts. Dear, I wish you were a human girl with a spankable bottom long enough for me to spank it-I would! In your memories is far more experience on which to judge than any flesh-and-blood can have. Quit dodging."

"Lazarus, no human can accept unlimited responsibility lest he go mad from unbearable load of unlimited guilt. You could have advised Libby's parents. But your responsibility did not extend even to that."

"Um. You're right, dear-it's dismal how regularly you are right. But I am an incurable buttinsky. Fourteen years earlier I had turned my back on two puppies, so to speak-and that the outcome was not tragic was good luck, not good planning. Now here we go again, and the outcome could be tragic. I felt no 'morals' about it, dear-just thumb rules for not, hurting people unintentionally. I didn't give a hoot if these children 'played doctor' or 'make a baby' or whatever the kids there called their experimenting; I simply did not want my godson giving little Libby a defective child.

"So, I did butt in and took it up with their parents. Let me add that Llita and Joe knew as much about genetics as a pig knows about politics. Aboard the 'Libby' I had kept my worries to myself, and never discussed the matter with them later. Despite their remarkable success in competing as free human beings, in most subjects Llita and Joe were ignorant. How could it be otherwise? I had taught them their Three R's and a few practical matters. Since arrival on Landfall they had been running under the whip; they hadn't had time to fill in gaps in their education.

"Perhaps worse yet, being immigrants, they had not grown up exposed to the local incest taboo. They were aware of it because I had warned them-but it wasn't canalized from childhood. Blessed had somewhat differenct incest taboos-but the taboos there did not apply to domestic animals. Slaves. Slaves bred as they were told to, or as they could get away with-and my two kids had been told by highest authority- their mother and their priest-that they were a 'breeding pair'...so it could not be wrong, or taboo, or sinful.

"It was simply something to keep quiet about on Landfall because Landfellows were tetched in the head on this subject.

"So I should have thought of it earlier. Yeah, sure, Sure! Minerva, I plead other obligations. I could not spend those years playing guardian angel to Llita and Joe. I had a wife and kids of my own, employees, a couple of thousand hectares of farmland and twice that much in virgin pinkwood- and I lived a long way off, even by high-orbit jumpbuggy.

Ishtar and Harnadiyad, and, to some extent, Galahad, all seem to think I am some sort of superman simply because I've lived a long time. I'm not; I have the limitations of any flesh-and-blood, and for years I was as busy with my problems as Llita and Joe were with theirs. Skyhaven didn't come to me gift-wrapped.

"It wasn't until we put aside restaurant business and I got out presents Laura had sent to their kids, and had admired the latest pictures of their kids and shown them pictures of Laura and my kids and all that ancient ritual, that I thought about it at all. The pix, of course. This tall lad, J.A., all hands and feet, wasn't the little boy I recalled from my last visit. Libby was about a year younger than Laura's oldest, and J.A.'s age I knew to the second-which is to say that he was about the age I was when I was almost caught with a girl in the belfry of our church about a thousand years earlier.

"My godson was no longer a child; he was an adolescent whose balls were not just ornaments. If he had not tried them as yet, he was certainly jerking off and thinking about it.

"The possibilities raced through my mind the way a man's past life is supposed to, when he is dying-which isn't true, by the way. So I tackled it and was subtle about it. Diplomatic.

"I said, 'Joe, which one do you lock up at night? Libby? Or this young wolf?'"

The computer chuckled. "'Diplomatic,'" she repeated.

"How would you have put it, dear? They looked puzzled. When I made it clear, Llita was indignant. Deprive her kids of each other? When they had slept together since they were babies? Besides, there wasn't room any other way. Or was I suggesting that she sleep with Libby while J.A. slept with Joe? If so, I could forget it!