From Der Spiegel:
The football World Cup from June 9 to July 9 last year appears to have sparked a baby boom in the host country Germany, where hospitals are reporting a marked rise in imminent births nine months after the tournament, remembered here as a month-long fairy-tale of sunshine, parties and soccer success.
The head of the largest birth clinic in the city of Kassel, Rolf Kliche, estimates that births at his hospital will be up by 10 to 15 percent, which he described as a “minor sensation” given the usually stable birth statistics.
Kliche said he wasn’t surprised because happiness tends to release hormones and makes it easier to get pregnant. “With many people the excitement they felt during the matches seems to have lasted and been employed in other ways after the final whistle,” he told Hessicher Rundfunk radio.
I’d also emphasize the enormous consumption of alcohol that takes place before, during and after European soccer matches. Hormones may be an important part in this “birth surge,” but I’d guess that beer plays an even more important role.