When do you want to have a baby? The answer depends on a lot of things, like your career, bank account balance, relationship status, and—according to a new study published in Human Nature—your choice of clocks.

To reach these head-scratching findings, researchers at Florida State University conducted two experiments in which they asked men and women about the about the age at which they wanted to get married and start a family, as well as what characteristics they wanted in a mate. During some of the interviews, a clock could be heard ticking nearby. During others, there was either a silent clock or no clock at all.

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The results: The women who sat in the room with the noisy clock wanted to get married and have children at a younger age—and they were more willing to settle in their romantic pairings to make that happen. Unsurprisingly, though, the tick-tock effects were strongest in women who were from backgrounds that prioritized having kids at a young age.

Researchers believe that by serving as a subtle reminder of the passage of time, ticking clocks make women more sensitive to their own biological clocks. However, the clocks didn’t have any effect on men’s answers, which the study authors attribute to men’s longer-lasting fertility.

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In the end, though, there are probably much bigger factors influencing when you decide to have kids—like when you find someone you want to have children with (or when you decide you want to pursue having kids without a partner) and if you get pregnant unexpectedly (or have trouble getting pregnant after you've decided you want to try to conceive).

The bottom line: The best time to have a baby is whenever you’re ready—and it's not always something that you can plan out in advance. If you do think you might want to get pregnant one day but aren't ready to start trying to conceive right now, read up on these totally doable ways to preserve your fertility.  

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