In a recent study, Bloomberg found that Hong Kong will be the world’s most crowded city by 2025. So far, so unsurprising – the city-state is an island, so a bigger population will mean a denser one. Acually, though, the study also found that the area’s population will increase far less rapidly in the coming decades than the swelling cities of South America or Saudi Arabia.

In fact, while the population is still expected to go up thanks to high life expectancies, Hong Kong’s birth rate is dismal. Since 1960, according to figures from the World Bank, it’s fallen from around 5 per women to just 1.3. That’s a more rapid decline even than that seen in mainland China, where the “one child policy” has been in place since 1979 (though it has recently been relaxed).

Low birth rates and long life expectancies are, unsurprisingly, leading to an aging population . By 2030, around a quarter of the city’s population may well be over 65.

So what gives? One explanation is that Hong Kong is a city, and people in cities tend to have less children than people in rural areas: space is at a premium, and you don’t need children to help out on the farm. In Shanghai, for example, there’s only around 0.9 births per women, compared to a China-wide average of 1.7. 

However, the Hong Kong Family Planning Association has come forward with a slightly different explanation. It’s all the women’s fault.

The association carried out a study, published in the Journal of Sexual Medicine earlier this year, which surveyed 2,146 21-40 year old women at birth control clinics and pre-pregnancy check-ups. It concluded that low levels of intimacy and sexual activity among women, plus something vaguely referred to as “sexual problems”, are to blame for the city-state’s falling birth rate. And before you ask, no – they didn’t carry out an equivalent study on men.

To solve the problem, Dr Lue So, the association’s senior doctor, has advised couples to “take turns to initiate coitus” and “have coitus two to three times a week and enjoy every moment”. Ah, the romance of spontaneity.

Not everyone is happy with this argument, and a recent Shanghaiist piece notes that blaming the birth rate on “lady problems” may be a little reductive: 

“It seems like the association’s opinion of Hong Kong’s low birth rate is more likely a result of the societal gender expectations that at best make the study biased and at worst may subconsciously affect these women’s physical desires.”

The article also points out that “frequency of coitus” (as Dr Lue So would put it) doesn’t necessary correlate with the number of births – especially as many of the women surveyed were found through family planning clinics, more often associated with contraception than conception.

Which raises the possibility that maybe people just don’t want to have children. Time to invest in some nursing homes.