system
Given the following post, respond as if you're commenting on Reddit:
human
What actually happens when a sperm and an egg of two different species meet?

If two beings that are genetically different enough that they cannot produce offspring actually mate, what happens?  Do they (the sperm and egg) not react at all?  Do they attempt a fusion but fail somewhere down the line?
gpt
Even if sperm were able to penetrate ovum, there are a host of issues past that.

First would be discrepancy in chromosome number. This would lead to cells with different numbers of chromosomes after mitosis. These cells would be unlikely to "work together" when it comes to signalling, chemotaxis, etc.

Secondly, different species express different genes at a genetic level. If you were to create some zygote between species different enough the gene expression would most likely result in cells unable to function, and it'd be a miracle if they progressed past a clump of cells.