Over the last decade, birth rates in Spain have dropped by 30%, from 486,000 births in 2010 to 339,000 in 2020, a decline only comparable to that seen in Japan and the Four Asian Tigers.

The main cause seems to stem from two major factors: (1) the widespread use of contraceptive methods, which allow for pregnancy control without reducing sexual activity, and (2) women’s entry into the labor market, leading to a significant shift away from traditional maternal roles.

In this regard, there is a phenomenon of demographic inertia that I believe could become significant. When a society ages and the population pyramid inverts, the burden this places on the non-dependent population could further contribute to a deeper decline in birth rates.

The more resources (time and money) non-dependent individuals have to dedicate to the elderly (dependents), the less they can allocate to producing new births (also dependents):

• An only child who has to care for both parents will bear a burden of 2 (2 ÷ 1).
• Three siblings who share the responsibility of caring for their parents will bear a burden of 0.6 (2 ÷ 3).

This burden on only children could, in many cases, be significant enough to prevent them from having children of their own.

In Spain, the generation of only children reached reproductive age in 2019(*), this means that right now the majority of people in reproductive age in Spain are only child (or getting very close to it).

If this assumption is correct, and aging feeds on itself, then, given that Spain has one of the worst demographic imbalances in the world, this phenomenon is likely to manifest through worsening birth rates. Spain’s current birth rate of 1.1 may not yet have reached its lowest point.

(*)Birth rate table and the year in which each generation reaches 32 years of age, Spain.