The fact is, humans share lots of genes with each other.

Example: Suppose I tell you, “What about language acquisition? I'm sure that if I speak better Italian than Nick Bostrom and he speaks better Swedish than me, our genes have f* all to do with that.” You could answer that it's our genes which shaped our brain in such a way that we could have picked up a native language in the first place, and a chimpanzee (or a human with major neurological problems) wouldn't have learned Italian or Swedish even if raised in the very same environment. But when more than 99% (I guess) of the world human population would have been able to learn whichever natural (or sufficiently natural-like) language they had been raised in, such an objection wouldn't be very useful.

On the other hand, while genes require environments in a given range to be expressed (you couldn't raise a person to be the same as me on Mars, even if he were my identical twin brother), certain features are expressed pretty much the same way throughout the range of environments where one could survive. The probability that John's blood type is AB+ given that he's alive and that his identical twin brother's blood type is AB+ is pretty close to 1, wherever John was raised.

Hence, I'd just say that language is environmental and blood type is genetic. Anything else is useless nitpicking, akin to saying that I shouldn't say that the C and C# keys on a piano are white and black respectively because even the former does absorb some light and even the latter does scatter some.

And everything scatters some of the incident light and absorbs some. But this doesn't mean we should never call anything “black” or “white”.