Click here to read "7 Things NEVER to Say to LGBT Coworkers." Click here to read "The 2008 DiversityInc Top 10 Companies for LGBT Employees." Click here for additional information about The DiversityInc Top 50 Companies for Diversity® announcement and dinner.

Under the new criteria, employers will have to grant employees access to "at least one insurance plan that contains no exclusions for transgender-specific care and recognizes internationally accepted medical standards of care."

Previously, the HRC required insurance plans to cover "one out of five categories of treatment that were designed to educate employers and their insurance carriers about the insurance needs of transgender people."

"These new criteria get right to the core issues of how insurance plans exclude transgender employees," Meghan Stabler, national transgender activist and HRC Business Council member, said in a written statement. "By aligning the new requirements to 'medically necessary' coverage defined by recognized standards of care and removing transgender-related exclusions from healthcare plans, we have significantly raised the bar allowing businesses to enhance their commitment to all employees. Right now, hundreds of businesses will begin working to expand coverage to transgender employees. With this powerful new tool, our community must set out to educate human resource and benefits professionals about why these benefits are needed, not just for individual employees and their dependents, but to secure employer-of-choice status in the LGBT community."

Other requirements to achieve a 100 percent HRC Corporate Equality Index rating include companies offering health-insurance access to same-sex partners and spouses, competency training and accountability on LGBT issues and external engagement in the LGBT community.

In addition to offering same-sex-partner insurance benefits, in order to get the 100 percent HRC rating, companies must also offer the same fringe benefits required by law for heterosexual couples, including medical and dependent coverage, COBRA-equivalent benefits, retirement benefits, FMLA-equivalent leave and bereavement leave.

This year, 39 of The 2009 DiversityInc Top 50 Companies for Diversity^® (74 percent) achieved a 100 percent rating on the HRC's Corporate Equality Index. In order to be considered as a DiversityInc Top 50 company, applicants must offer benefits to same-sex partners of employees.

The 2009 DiversityInc Top 50 Companies for Diversity will be announced Thursday, March 12, at a dinner at the New York Marriott Marquis. In addition to The DiversityInc Top 50 Companies for Diversity list, DiversityInc also prepares a series of specialty lists, including the best companies for LGBT employees.