Health has long been a priority of the foundation, since Gates read an article about poor people dying of preventable diseases. He sent the article to his father, Bill Gates Sr. who runs the foundation, with a note attached that read: "Dad, maybe we ought to try to do something about this."

Justa few years ago Bill Gates, Jr. was criticized for being parsimonious when it came to charitable giving, but he has proven himself a powerful late bloomer.He resisted his parents' early encouragements to start a charitable fo undation in-step with Microsoft, preferring to concentrate of the sustainability of thecompany. "That didn't last long," said his father.

Indeed,the Bill and Melinda Gates Foundation is now the largest charity in the world, with an estimated $24.2 billion endowment. To keep pace with federal philanthropy laws the foundation must give away roughly $3.3 million per day,or $1.2 billion a year (5% of the overall endowment). The 221 employees, modestfor a foundation of this scale, receive roughly 2,000 requests for money a day. Butmany of their practices have come under fire, and the foundation has been labeled 'liberal,' by many of its critics. For example the $1 billion college fund for minorities was criticized as promoting affirmative action, and a donation to family planning has drawn protest from anti-abortion groups.

The most recent criticism has come of the Global Alliance for Vaccines and Immunization (GAVI), a division of the foundation launched two years ago. The foundation has campaigned and become one of the largest private donors globally to eradicate and vaccinate against such diseases as yellow fever, hepatitis B, malaria, tuberculosis, and African sleeping sickness.

The international business of vaccinating those residents of the world's poorest nations has traditionally been an under-funded and bureaucratic process. Some experts in the field have criticized the Gates Foundation's strict auditing policies, although failure to meet the stringent standards so far has not resulted in any withdrawal of funds.

"Are we being ridiculous, expecting this quality of recording in poor countries?" asked leading auditor Vicki Doyle, a Ph.D. in health systems from Liverpool, England. "You just can't have this huge fund and none ofthe countries qualifying for a second round of funding. Then all you're left with is a big failure."

Gates has argued in the past that developing countries can benefit from development funding-corporate style, with inceptives and imposition of performance targets,which push them to be more efficient. The organization also has said that first-year audits would not result in any aid cutoffs, but that it planned to perform audits in all recipient countries in 2002 and would suspend funding on a case-by-case basis if necessary a decision that will come as no surprise to Amos Chweya, Kenya's vaccine control officer.

"The days when people just bring in vaccines as we ask for them," said Chewya, "are long gone."

Kenyahas received $600,000 and vaccines for two million children from GAVI, but auditors have encountered rampant disorganization, distribution problems, and ageneral lack of knowledge about the program.

Every donation over $1 million is personally reviewed by Bill and Melinda Gates, and the charity has no board which they consult. So, ultimately, the decision on who to fund, and how and when lies in the hands of the richest couple in the world, whose personal fortune (the bulk of which Gates has said will eventually go to the foundation) is estimated at $54 billion.