Dr Satoshi Kanazawa, an evolutionary psychologist at the London School of Economics, claims to have analysed results from an online poll that proves they are rated generally less good looking than women with different coloured skins.
Using findings from a study of physical attractiveness by Add Health, he claims the results show that 'black women are... far less attractive than white, Asian, and Native American women.'
But his comments on a blog for the website of the journal Psychology Today caused a storm of outrage with hundreds of people writing to the magazine claiming his comments are racist.
The blog was removed but irate readers are demanding a retraction form the scientist - believed to be of Japanese origin - and the magazine.
Dr Kanazawa based his assertions on analysis of a website that asked people to assess the relative attractiveness of various people on a scale of one to five.
He claimed that the results show that while black women scored on average 3.5 out of five, other races including European, Asian and native American scored 3.7.
In contrast black men, he said, were more attractive than their other males.
He then attempts to justify the findings, claiming that black women are on average heavier than non-blacks and that because they are an older race, they have more mutations in their genes.
He finally argues that they have more of the male hormone testosterone which suggests they will have more manly features.
"Black women are on average much heavier than non black women," he said.
"However, this is not the reason black women are less physically attractive than non black women.
"Because they have existed much longer in human evolutionary history, Africans have more mutations in their genomes than other races."
"But since both black women and black men have higher mutation loads, it cannot explain why only black women are less physically attractive, while black men are, if anything, more attractive.
"The only thing I can think of that might potentially explain the lower average level of physical attractiveness among black women is testosterone.
"Africans on average have higher levels of testosterone than other races... women with higher levels of testosterone have more masculine features and are therefore less physically attractive."
But his comments created a barrage of criticism.
One comment said it was "so outrageous that we almost thought it was a hoax of some sort".
Another writes: "Justifying racism using 'science' isn't new, by any means.
"Every few years, it appears that someone needs to provide a rationale for bigotry, so they publish some sort of madness and hope most of the readers suffer from scientific illiteracy.
The post has since been removed from the Psychology Today amid a backlash.
Kaja Perina, Psychology Today's editor-in-chief, said: "Our bloggers are credential[ed] social scientists and for this reason they are invited to post to the site on topics of their choosing.
"We in turn reserve the right to remove posts for any number of reasons. Because the post was not commissioned or solicited by PT (in contrast to a magazine article), there was no editorial intent to address questions of race and physical attractiveness."
Dr Kanazawa has an online column on Psychology Today called "A Look at the Hard Truths About Human Nature".
It includes posts with titles such as: "Are All Women Essentially Prostitutes?', "If Beautiful People Have Daughters, Why Do Posh and Becks Have Three Sons?", "More Intelligent People Are More Likely to Binge Drink and Get Drunk" and "Girls Are More Intelligent Than Boys, But Men Are More Intelligent Than Women".
A spokesman for the LSE said they had launched an investigation into the blog.
"The views expressed by this academic are his own and do not in any way represent those of LSE as an institution," he said.
"The important principle of academic freedom means that authors have the right to publish their views – but it also gives others the freedom to disagree."
Dr Kanazawa was unavailable for comment.
