Boris Johnson's adviser who voiced support for eugenics has resigned

Britain's Prime Minister  Boris Johnson faced calls to dismiss a controversial adviser.

London (CNN)A recently hired adviser to British Prime Minister Boris Johnson has resigned, after backlash grew against his controversial past comments -- notably for claims that black Americans have lower IQs than white Americans and that compulsory contraception could prevent the creation of a "permanent underclass."

Andrew Sabisky, a self-described "superforecaster," announced his resignation as a "contractor" on Twitter Monday, saying that he did not want the "media hysteria about my old stuff online" to be a distraction for Johnson's government.
"I know this will disappoint a lot of ppl but I signed up to do real work, not be in the middle of a giant character assassination: if I can't do the work properly there's no point, & I have a lot of other things to do w/ my life," he said in another tweet.
    The 27-year-old was hired by Johnson's most senior adviser, Dominic Cummings, who advertised earlier this year for "weirdos and misfits with odd skills" to work alongside him.
    Critics of the appointment singled out past comments made by Sabisky in support of eugenics and giving children mind-enhancing drugs for their educational benefits. "From a societal perspective the benefits of giving everyone modafinil once a week are probably worth a dead kid once a year," he said in a 2016 interview.
    In a 2014 comment on Cummings' website, Sabisky wrote: "One way to get around the problems of unplanned pregnancies creating a permanent underclass would be to legally enforce universal uptake of long-term contraception at the onset of puberty."
    "Vaccination laws give it a precedent, I would argue."
    In a post on another website in 2014, he also suggested that black Americans have a lower average IQ than their white counterparts.