The Bill and Melinda Gates Foundation, to which Buffett has pledged the bulk of his $44-billion fortune, devotes the vast majority of its funding to combating disease and poverty in developing countries. Less than 1 percent has gone to Planned Parenthood over the years. And the Gates Foundation does not permit its gifts to Planned Parenthood to be used for abortion services.
"The merger of Gates and Buffett may spell doom for the families of the developing world," said the Rev. Thomas Euteneuer, a Roman Catholic priest who is president of Human Life International.
Referring to Josef Mengele, the infamous Nazi death camp doctor, Euteneuer said Buffett "will be known as the Dr. Mengele of philanthropy unless he repents."
Beyond the issue of abortion, some critics oppose the Buffett and Gates foundations' support for global family-planning and population control programs.
"Some of the wealthiest men in the world descend like avenging angels on the populations of the developing world," wrote Population Research Institute president Steven Mosher, a frequent critic of Gates and Buffett. "They seek to decimate their numbers, to foist upon vulnerable people abortion, sterilization and contraception."