DECLINE IN SEX-RATIO AT BIRTH AFTER KOBE EARTHQUAKE

We investigated the possible association between the Kobe earthquake ( January 1995) and the sex ratio among liveborn infants after the catas trophe. A significant decline in the sex ratio (0.501) of Hyogo Prefec ture in October 1995 was observed 9 months after the Kobe earthquake a s compared with an expected value of 0.516 in the period from January 1993 to January 1996 (P = 0.04; one-tailed). Simultaneously, a reducti on in fertility of similar to 6% was also observed, compared with the month of October 2 years previously Thus, the acute stress resulting f rom a great natural catastrophe can be a cause of a low sex ratio at b irth 9 months later.