Editing Time Enough for Love (section)

==="The Tale of the Twins Who Weren't"===
Lazarus tells of his visit as an interplanetary cargo trader to a planet, where he bought a pair of slaves, brother and sister, and immediately [[manumission|manumitted]] them. Because they had no knowledge of independent living or any education, Lazarus teaches them "how to be human" during the voyage.

The two were the result of an experiment in genetic recombination in which two parent cells were separated into complementary [[haploid]] [[gamete]]s and recombined into two embryos. The resulting [[zygote]]s were implanted in a woman and gestated by her, with the result that although both have the same surrogate mother and genetic parents, they are no more closely related genetically than any two people taken at random. They have been prevented from sexual relations by a [[chastity belt]]. However, having confirmed that there is no risk of genetic disease in their offspring (described as the only valid argument against [[incest]]), Lazarus solemnizes their marriage and later establishes them as the owners and operators of a thriving business. At the end of the story, he reveals that the twins looked the same age decades later and expresses his belief that they were his own descendants, from an earlier time that he had been a slave on the same planet.