Except fasting, sometimes to the point of death. Food is available but we can choose not to eat it.

Breathing can also be overcome by willpower and sapience, you can hold your breath as long as you like (until you pass out and you lose your sapience by way of being unconscious, and the autonomic systems engage which continue to respirate for you.

People have a choice to drink the same way fasting works.

Even fight or flight can be overcome. A notable example of overcoming some of the most basic instincts is the self immolation that some people have committed where they simply sit and burn rather than react in any other way (screaming, running, stop/drop/rolling, etc). There was a very public and newsworthy instance of this from a monk, who literally sat there, basically mediating while he burned to death.

Pretty much anything that you feel a drive for, can be overcome, as long as you have the sapience and willpower to overcome it. Autonomic functions are basically immutable, so something like breathing is impossible to stop if you are not conscious to actively prevent it.

Sapience and willpower can overcome any natural drive or desire as we see fit.

I will recognize that getting people to agree to do something on a mass scale is generally impossible. Like herding cats… It’s doubly hard when that thing goes against their more basic desires.

It’s been known to happen, but the instances are few IMO. Something like reproduction however, without a law or government mandate, it would be hard to prevent people from making more people and growing the population. Most notable example of this is countries where there are limits on how many children you can have. They’re successful, with some fairly horrendous stories of the consequence of non-compliance, and horror stories of what people have done to try to abide by the laws while still having what they desire (perhaps a child of a certain gender?).

One of the natural drives is to have children. Multiple of them. Some, like me and my friends, have chosen not to do that. Sapience > natural drive. Limiting how many children a person may have is difficult, as we’ve witnessed from the countries that tried it, so making MORE children because we have the room/resources for it becomes a more natural outcome if the population was suddenly cut in half.

Hell, if such a thing happened, and by some miracle my partner and I both survived the culling, I’d have a serious conversation with them about maybe changing our minds on the childfree thing. But that’s a discussion that won’t happen because Thanos isn’t real and can’t hurt us.