Wait... was Tooru the real stand user all this time and the doctor himself is his stand? Seems odd that he'd know that something weird is happening on the lab otherwise, then again since stands are supposed to have the voice of their user (which this stand would've shown when it momentarily...
If they're not blood-related then no, it's absolutely not incest from a scientific standpoint, though it might be seen as incest from social perspective and can thus carry some stigma regardless of the presence of genetic problems.
On a semi-related note, I've seen an argument claim that if you...