An egg lives for around 12 hours after ovulation. Sperm can live for about five days inside the uterus, so providing those two time frames collide, it can be pretty soon after sex. Hours, usually. Implantation occurs between 6 - 12 days.
The word eugenics was coined in 1883 by the English scientist Francis Galton, a cousin of Charles Darwin, to promote the ideal of perfecting the human race by, as he put it, getting rid of its undesirables while multiplying its desirables -- that is, by encouraging the procreation of the social Darwinian fit and discouraging that of the unfit ...
The term Fertile Crescent was popularized by University of Chicago archaeologist James Henry Breasted, beginning with his high school textbooks Outlines of European History in 1914 and Ancient Times, A History of the Early World in 1916.