First, thank you for providing the source.
Second, Blanchard's "research" has been exposed as flawed, and that's putting it mildly. Blanchard has been debunked by the psychiatric community for his faulty scientific research methodology aimed at pathologizing transsexual people.
He started with an agenda that divided male-to-female transsexual people into two different groups: "homosexual transsexuals" who seek reassignment surgery to romantically and sexually attract other, ideally heterosexual, men, and "autogynephilic transsexuals" who are sexually aroused at the idea of having a female body. Although this makes distinctions between transsexuals it does not place any of these distinctions in any sort of context. In short, he reduces all of our relationships to paraphilia, and no notions of gender identity are entertained or tolerated.
As further evidence of his haphazard process you might notice that he did no work at all with transmen.
It has been suggested that his "research" was largely aimed at satisfying his own transgender fetish; his findings are very much in vogue with fetishists.
Scientific criticism of his "research" and theory argues that his theory is incomplete and poorly representative of MtF transsexual people, reduces gender identity to a matter of attraction, is non-instructive, and that the research cited in support of the theory has inadequate control groups or is contradicted by other data.
Another note - his theories have led to support for reparation or conversion therapy which itself has been debunked to the point where not only is it not practiced by legitimate therapists it is actually illegal in many jurisdictions.
His disciple Ken Zucker followed Blanchard's methodology and, long story short, was eventually disciplined by the university where he worked and essentially warehoused by shifting most of his courses to another department within the university and leaving him with nothing to do and no opportunities to publish, thus effectively ending his career. Similar fates have befallen others who have followed in his footsteps.
In short, he remains at odds with the psychiatric community and his efforts to pathologize transgenderism in the previous DSM have been overturned in the soon-to-be-published version. His ideas are, at best, antiquated and have been superseded by more advanced studies and legitimate, productive therapies.