The company handling the Women’s Tennis Association’s controversial genetic sex screening has identity questions of its own—and neither the company nor the WTA appears eager to answer them.

Phuel Sports Science, a Colorado-based firm behind a performance blood-testing service, was chosen by the WTA to perform a one-time SRY gene screening test to identify the biological sex of competing athletes. The test is mandatory under a new eligibility policy enacted by the professional tennis tour that broadly restricts player participation to biological females, the first known implementation of such a policy in a major women’s sports league.

Yet basic information about the company entrusted with carrying out this mission is difficult to come by. Phuel founder and long-time CEO Garret Rock downplayed his current involvement in the company this week and declined to provide information on its current leadership. Multiple phone and email messages left with Phuel went unanswered. And the WTA has been similarly tight-lipped, telling Sportico it “will not be commenting on the private screening process including matters related to service providers.”

Independent tennis journalist Ben Rothenberg was first to report in his newsletter, Bounces, that Phuel had been selected to conduct the screening.