STOCKHOLM — Famous for its efforts to put women on an equal footing with men, Sweden is experiencing a gender shift that has caught the country by surprise: For the first time since record-keeping began in 1749, it now has more men than women.

Swedes don’t quite know what to make of this sudden male surplus, which is highly unusual in the West, where women historically have been in the majority in almost every country. But it may be a sign of things to come as changes in life expectancy and migration transform demographics.

‘‘This is a novel phenomenon for Europe,’’ said Francesco Billari, a University of Oxford demographer.

The tipping point in Sweden happened in March last year. The gap has since grown to beyond 12,000.

Norway swung to a male surplus in 2011; Denmark and Switzerland are nearing a sex ratio of 100.

Swedish officials say the shift is mainly due to men catching up with women in terms of life expectancy. The arrival of tens of thousands of unaccompanied boys from Afghanistan, Syria, and North Africa is also having an impact.

Associated Press