Labour is calling for the immediate sacking of a Tory adviser over his controversial remarks about pregnancy, race and women’s sport.

Oxbridge-educated Andrew Sabisky is working as a No 10 adviser, having been appointed after chief aide Dominic Cummings put out a job description for “misfits and weirdos” to join him in trying to shake up government.

The 27-year-old, who is contracted on specific projects and is not a permanent staffer, wrote on Cummings’ website in 2014 than in order to get around unplanned pregnancies in the UK, there should be the legal enforcement of long-term contraception.

“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 and the onset of puberty,” he wrote. “Vaccination laws give it a precedent, I would argue.”

In another post circulated on Twitter, Sabisky claimed black Americans had a lower average IQ than white people and were more likely to have an “intellectual disability”. He also tweeted: “I am always straight up in saying that women’s sport is more comparable to the Paralympics than it is to men’s.”

Jon Trickett MP, Labour’s shadow cabinet office minister, said: “There are really no words to describe Boris Johnson’s appointment as one of his senior advisers a man who is on record as supporting the forced sterilisation of people he considers not worthy. He must of course be removed from this position immediately.”

Labour MP David Lammy condemned Sabisky’s post about the IQs of black and white Americans as “dangerous claptrap”. He tweeted: “Andrew Sabisky has some very ugly views, but depressingly he’s not alone. There is a resurgent belief in Eugenics across fringes of the right. It’s dangerous claptrap. Skin colour has no more relevance to an individual’s intelligence than their hair colour.”

Sabisky, who describes himself as a political forecaster, has also deleted tweets calling Labour MPs Angela Rayner, Rebecca Long-Bailey and Yvette Cooper “dim”.

His hiring has been widely criticised on social media, with many questioning how he got through strict government vetting processes.

In an interview he did in 2016 Sabisky said he was interested in narcolepsy drug modafinil, which also cuts the need for sleep in healthy people by two-thirds and potentially helps brain function.

There is also evidence of a higher risk of people getting Stevens-Johnson syndrome, a life-threatening skin condition. “From a societal perspective the benefits of giving everyone modafinil once a week are probably worth a dead kid once a year,” he said.