This is not a belief you want to hold on to. Neuroscience is a VERY new field and while genetics has been around for quite some time it can't explain sexual preferences consistently. The soft sciences are currently under crises because of failure of reproducibility.
But... it's about 1% right. Which is okay. Let me explain.
In humans it has not been 100% confirmed whether there is a link between mate selection and scent but it's confirmed in lab rats and various mammals. There were experiments done on lab rats to determine this. They did this by spraying baby rats with a lemon scent and then seeing who they would choose later on in their life for mate selection and the results show a clear link between baby's exposure to a scent and later mate selection in adulthood. The study
https://pubmed.ncbi.nlm.nih.gov/7122734/
Rats have an organ in their nose that goes through the process of learning a scent which is usually a female in the beginning. It is known as imprinting and it's not confirmed in humans at least not in THIS way FOR mate selection. Comparative zoology would have you believe that it must naturally be there but humans are WAY more complex than rats.
On the neuroscience perspective it's even more interesting. It's also WAY more difficult to do studies on humans. There's at least two competing theories on how the brain works but it can be boiled down to nature vs nurture. And neither of them win with any certainty. And in fact they may not win at all because human brains don't work that way. A new third theory is popping up that throws that out the window that I don't quite understand but it's clear that there's no consensus at least right now among neuroscientists.
What this implies is that genetics is poorly correlated with human nature. Not that that was ever settled WITH HUMANS. Maybe with some cute peapods (or not. Problems with the mendel studies but that's unrelated) but not with humans.
Psychology certainly doesn't have a base to stand on but not because humans are unreliable. It's because psychology is incredibly hard to reproduce. You pretty much have to work backwards. Find some social correlation and trace it back to a gene which is unlikely to work because the brain is involved which just makes things a bigger pain. And don't even get me started on the problems with the statistical analysis done on these studies.
As far as I can tell people have a serious misunderstanding of science. People seem to want to idolize science and make weird connections between facts and science. Science is NOT about facts. I guess this is what happens when you're bored. If you're not a good fiction writer well then just make up whatever on a forum about suicide.