With great care, in an operation taking three days, they scooped the original genetic material out of the ovum, replaced it with the material they had tailored from Amanda, introduced the equivalent material from Sarek, closed the little cell up ... and waited. It sat thinking for about half an hour, and then divided. And divided again. And again. They did not cheer: they were Vulcans. But there was an insufferable air of satisfaction about the Parturitic Genetics lab for days.

— “Vulcan: Seven,” Spock's World