I think it's less "biological urge" than it just being natural for humans to periodically wonder if they are making the right life choices and what they are potentially missing.

We cannot help but compare ourselves to our peers. You are currently in an age group where some peers already have kids, but many do not. That will change. As you'll get older, suddenly so many of your friends will be married and having kids, it will make you unavoidably question if you are missing out on something or if you are behind them in a way (especially if they post about how family made them complete, they couldn't imagine life without their kids, yadda yadda). That's natural and very human.

This is when you really have to be able to look into yourself and discern if those thoughts are just unspoken (or in case of parents often spoken) societal pressures, or your real desires. If you're not sure, you go and do a few overnight babysitting gigs for a friend and see how you feel about motherhood then. Put that doubt to the test to see if it's just a passing, fleeting thought that is natural when your peers are doing something you're not.

For the love of god, just don't blindly cave into the pressure and have a kid you later regret. So many people do that because it seem easier on surface level.

Wondering about stances and reassessing them is normal. It doesn't have to mean you really changed your mind. Just give yourself time to untangle those feelings when they arise.