Up on the seventh floor of Building 16 at the Massachusetts Institute of Technology (MIT) in Cambridge, biological engineer James Sherley already has his schedule for 1 July mapped out. “I plan on coming into my office, just like I normally do,” he says. “They'll have to come in here and drag me out.”

Time is running out for the stem-cell researcher — a year and a half, one hunger strike and countless e-mails after being denied tenure. MIT has told him that 30 June is his last day. But Sherley has no intention of going quietly.

Sherley, who is African-American, has argued that racial discrimination and colleagues' conflicts of interest marred his tenure process. Under-represented minorities (African-American, Hispanic and Native American) make up only 3.6% of the senior faculty at MIT; the US national average is 3.5% in natural science and engineering at élite research universities.

I am being denied something that I deserve because of my race.

“I am just tired of racism,” says Sherley. “Here I am again at a point where I am being denied something that I deserve because of my race.”

Frank Douglas, who is African-American, also resigned in protest as executive director of MIT's Center for Biomedical Innovation this month: “I leave because I would [not] be able to advise young Blacks about their prospects of flourishing in the current environment.”

Sherley says signs of discrimination were evident from the moment he arrived at MIT, eight years ago. Requests to expand his lab space were denied, he says, and his lab was rarely invited to speak at departmental seminars.

In March, faculty members at the biological engineering department expanded on their decision not to grant Sherley tenure, saying the process was “as free as humanly possible from bias and racism”. “External letters from experts in the field of stem-cell biology were not strong enough,” they wrote. They point out that two-thirds of the $1.5 million in external funds used to fund Sherley's pre-tenure research came from grants on which Sherley was not the primary investigator. On average, only a third of MIT assistant professors receive tenure.

During the years before the decision, Sherley published six peer-reviewed research papers. Of the two other candidates in his department who were awarded tenure around the time when Sherley's case was being considered, one had published 12 papers during the same period, the other 18. Both bodies of work were cited on average twice as often as Sherley's. However, the value of Sherley's research cannot be appreciated merely by counting citations, says George Church, a Harvard University biologist. “It takes a little digging to see it,” he says. “They don't give him any credit for the creativity.”

Sherley has tackled several open questions in stem-cell biology. He re-evaluated the 'immortal strand' hypothesis proposed more than 30 years ago as a mechanism by which adult stem cells prevent the accumulation of mutations in their DNA. In 2006, after his tenure application was denied, Sherley was awarded the National Institutes of Health Director's Pioneer Award for challenging research directions.

Not everyone feels Sherley's work warrants tenure. “I thought the decision not to grant tenure was correct,” says Nancy Hopkins, an MIT biologist who led the institute's evaluation of gender equality in the late 1990s. “I did not detect bias that affected this outcome. However, unintentional racial bias, like gender bias, is unavoidable in our society.”

Biological engineer James Sherley claims racial discrimination cost him tenure at MIT. Credit: C. SUZUKI/AP

Some speculate that Sherley's controversial opposition to embryonic stem-cell research was a factor. Sherley, who studies adult stem cells, has been critical of embryonic stem-cell research on ethical and practical grounds.

Sherley ended his March hunger strike after 12 days, when, according to him, MIT agreed to re-evaluate his case. MIT says no such agreement was ever made and no further investigation is needed. Sherley says that MIT has failed to hold up its end of the bargain; the university says that the inquiry held before the strike by a committee of senior faculty members, who were approved by Sherley, is sufficient.

His complaints have triggered one change, though: after the hunger strike, MIT announced a new initiative on race. It includes a study modelled on the 1999 investigation led by Hopkins on female scientists, and aims to quantify differences such as salary, lab space and the time between tenure and promotion to full professor. The study is due to be completed in September 2008.

For Sherley, the results will come too late. “His term as a member of the faculty ends on 30 June,” says MIT chancellor Phillip Clay. “The review process is complete.”