Male violence no longer news

There's a "gene for violence" in the news. What I want to know: Why is more not being made of the gene being X-linked, and with the violent phenotype correlating with gene underexpression? That's a recipe for exclusively male violence [Eds. note: Recall girls have a backup "X," while boys have only that relatively useless "Y," that "X-linked" means a gene is on the X chromosome, that "phenotype" is a word you can often ignore and contrasts with "genotype," and meanwhile let me invite you to just trust me that "underexpression" means that the abnormal version of the gene sort of fizzles, as opposed to producing an abundance of the wrong thing ]. Ah well. Gender schmender. Nobody cares about such stuff in this enlightened day, even if it does turn out to be rooted in biology.