This was one of the topics of the day in Japan on Aug, 16, 1966: (From Google search.)
"What explains Japan's sudden birth-rate decline in 1966 is the fact that 1966 was a year of Hinoeuma. For according to the superstition, any girl born in such a year will be of harsh temperament and invite misfortune in other words, she will have great difficulty finding a husband. The Japanese just weren't taking that chance. Rather than conceiving children on the chance that they would be boys and thus immune to the misfortunes of Hinoeuma, many Japanese decided to wait till next year. During 1965 and early 1966, they practiced rigorous birth control. And failing that, they were quite prepared to resort to abortion to make certain that they brought no unlucky daughters into the world. "
Far out, man!
John