[psunavy03]

My brain spent about 2.5 seconds wondering how the hell you spay or neuter a rat before giving up.

[pgeorgi]

It can be done to drosophila, as alluded to in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3197105/

[clort]

I'm sure I read a [news] story about this many years ago and have wondered what became of it, perhaps these guys?

https://senestech.com/contrapest/

[strken]

It's expensive and risky, and it can be hard to find a specialist vet. I kept pet rats once, and it was easier to just separate the males and females from each other.