Adoptive working parents seem to have fewer supports at their disposal, according to a  recent report released by the Washington-based Institute for Women’s Policy Research. While the federal government treats them equally under the Family and Medical Leave Act–a federal law that allows certain employees to take up to 12 weeks of unpaid, job-protected leave to care for new babies, sick relatives or oneself because of illness–it seems that some employers treat them as second-class citizens.

Nationwide statistics about adoption benefits are hard to come by. But an institute survey of the 100 “best companies” for working mothers listed in Working Mother magazine shows that leave benefits for adoptive parents were less generous than those for biological ones.

Nearly three-quarters of the companies surveyed offer more than four weeks of paid leave to biological mothers, but only one-third offer more than four weeks of paid leave for adoptive parents, according to the institute. Fourteen percent of these companies, meanwhile, offer more than 12 weeks paid leave to biological mothers, but none offer the equivalent to adoptive parents.