Sir

Your Editorial 'The female underclass' highlights the problems faced by women scientists in many European countries (Nature 459, 299; 2009). I'd like to comment on the situation in the United States.

Taking the biological and medical sciences, for example: from 1990 to 2004, the percentage of traditional research awards from the US National Institutes of Health (NIH) allocated to women grew from a paltry 17% to just 24% (see http://tinyurl.com/kvtvhc). Only 19% of tenured principal investigators at the NIH are women. These figures have hardly changed over the past decade and are dishearteningly similar to those at most academic research institutions in the country (see http://tinyurl.com/kpav3j).

Yet there have been more female than male graduate students in these fields over the same period. In 2005 the number of doctorates awarded to women overtook the number awarded to men (see http://tinyurl.com/nemfs6). Although women make up nearly half of all scientists nationwide, many abandon academic research after a decade.

What is happening to these female graduates, and what can explain the startling drop-off in figures? It's simple. Report after report has documented gender bias. For example, the 2007 report from the US National Academies, Beyond Bias and Barriers: Fulfilling the Potential of Women in Academic Science and Engineering, categorically affirms bias against women applying for grants, employment and tenure. It asserts that a woman must have a significantly superior record to be rated on a par with a man. And it rejects out of hand the purported meritocracy that determines hiring, promotions and rewards in academic institutions.

The loss of women scientists has also been attributed to their relative lack of confidence in seeking positions and securing tenure (EMBO Reports 8, 977–981; 2007). Of course they are less confident — a woman is only too aware of the time and energy she must invest in overcoming bias and building up a “significantly superior record”.

If we ask what has worked in those European countries that have managed to curtail destructive habits of bias and exclusion, again the answer is simple. As you point out, it takes “sticks as well as carrots”. No sensible man would give up his advantage by conceding that he is intellectually inferior to a female colleague. And no university yet seems prepared to remove men who are guilty of blatant acts of bias.

What is at stake is not only justice: it is the competitiveness of science in the United States. When half of our brightest scientists leave academic research because their intelligence and common sense tell them they are wasting their considerable skills, how can we possibly generate the best science?