Are Dogs Replacing Children?

Testing the Boss Baby Hypothesis

In DreamWorks’ The Boss Baby (2017), babies and puppies are locked in a comic competition for adults’ love. The film turns a demographic worry into a corporate thriller: what if the puppy industry became so irresistible that babies lost their place in the family economy?

It is a ridiculous premise, which is exactly why it is memorable. It is also surprisingly easy to translate into a real hypothesis: if dogs substitute for children, countries with more dogs should have lower fertility. More importantly, increases in dogs should come before declines in fertility. And if the arrow runs the other way (if falling fertility makes dogs more attractive) then fertility should move first.

Brad Hargreaves made a very similar real-world argument in his July 2025 Thesis Driven essay “On Urban Dogs,” and in the tweet that circulated alongside it. He pointed to U.S. dog-owning households rising from 48.2 million in 2016 to almost 60 million in 2024, pet spending more than doubling, and fertility falling below replacement. His stronger claim was directional: young urban couples acquire a dog instead of having a child, and the dog’s later demands on money, space, and time can even help prevent a second child. That is a testable version of the Boss Baby hypothesis: not merely “dogs and fertility changed at the same time,” but “dogs came first and pushed fertility down” (Hargreaves, 2025).

The joke also has a real scholarly shadow. A recent Taiwanese working paper linking pet-registry records to tax records reports that adopting a dog was followed by a 33% increase in the probability of subsequent childbearing, while births also changed later dog adoption. This evidence is more compatible with dogs and babies as complements than substitutes (Chen et al., 2025). Other studies point toward substitution, but mostly for fertility intentions rather than completed births: stronger pet attachment was associated with lower fertility intentions among higher-SES respondents in a Chinese study (Guo et al., 2021), while interviews with childfree companion-animal owners and an ethnography of Israeli couples describe pets as “prechildren” or satisfying substitutes for some people (Laurent-Simpson, 2017; Shir-Vertesh, 2012). Those studies are important, but they concern intentions, narratives, or selected couples, not population-level fertility effects.

That leaves three competing mechanisms. Substitution is the Boss Baby story: dogs absorb money, time, care, or emotional investment that might otherwise support children. Complementarity is the opposite possibility: acquiring a dog may be part of a transition toward parenthood, a “practice child,” or a family lifestyle that later includes children. Reverse causality runs from family formation—or from declining fertility, childlessness, or weaker social networks—to dogs: households with children may be more likely to acquire or retain pets, as life-course research has long suggested (Albert and Bulcroft, 1988).

So: does the Boss Baby have a point?