BRUSSELS: Justine Henin has gone from confirming she won't return to competitive tennis to refusing to discuss her future.

The retired Henin was asked again Thursday if she would return to the sport. The answer is no longer the definitive "no" it once was. It is now something more like, "Come back and ask me later."

A UNICEF goodwill ambassador, she tried to keep the press conference focused on tetanus vaccinations for mothers and babies in developing nations.

"We are here to discuss child mortality in the world, a subject matter which is important enough to center on this today," she said at UNICEF headquarters.

Last year, Henin shocked the tennis world by announcing her retirement while ranked No. 1. In May, she said the sport had left her with so many physical pains that a return was unthinkable.

Yet she was seen training again recently, apparently for a small exhibition tournament in southern Charleroi, one she has played in regularly during the December winter break.

Some wonder if the exhibition will have the same impact as it did on Kim Clijsters. After retiring two years ago, she played an exhibition at Wimbledon this spring to test the new retractable roof. It got her competitive fire burning again.

Clijsters returned to the tour last month, and will play in the semifinals of the U.S Open on Friday.

Henin also pulled out of a theater commitment, fueling rumors that she needed time for tennis practice.

On Thursday, she deflected such questions. Four months ago, she said competitive tennis "is truly a page that has been turned."

She was asked about Clijsters' surge and the surprise run of teenager Yanina Wickmayer, landing two Belgians in the semifinals of the U.S. Open.

"It is magnificent, that is evident," Henin said. "But understand that I am here in my role as ambassador."

Over the past months, Henin has traveled to Congo, Cambodia and Denmark to learn more about child vaccinations and how it affects survival for hundreds of thousands of poor mothers and babies around the world. Her face will become the face of the UNICEF tetanus campaign this fall.

"I have been able to discover so many things in my life after tennis," she said. "You live in a bubble and in leaving it, you ask plenty of questions on plenty of issues."

At 27, it would certainly not be too late for a comeback. As the 26-year-old Clijsters has proved, breaking back into the top at short notice is possible.