New research on asexuality shows why it’s so important for doctors and therapists to distinguish between episodes of low libido and a consistent lack of sexual attraction
…
Over the past two decades psychological studies have shown that asexuality should be classified not as a disorder but as a stable sexual orientation akin to homosexuality or heterosexuality. Both cultural awareness and clinical medicine have been slow to catch on. It's only recently that academic researchers have begun to look at asexuality not as an indicator of health problems but as a legitimate, underexplored way of being human.
In biology, the word “asexual” typically gets used in reference to species that reproduce without sex, such as bacteria and aphids. But in some species that do require mating to have offspring, such as sheep and rodents, scientists have observed individuals that don't appear driven to engage in the act.
To be fair, culture is always extremely slowly for everything, when it's going forward in the first place.
As for clinical research, i'd say the field is what's new. So i don't expect it to be quicker than common sense before a century at least.