[5] While still graduate students, they and Jean Black co-founded a retail and mail-order business called Adam and Eve, selling condoms and sex aids in the United States and internationally in order to use the profits to finance family-planning programs in developing countries.

While serving as PSI directors, Tim and Jean Black moved to Kenya from 1970 to 1974 to set up a PSI-run Contraceptive Social Marketing[6] pilot program, which with support from USAID and other agencies would later be expanded to other African countries.

[7] In 1971, the PSI Board was expanded through the addition of Dr. Geoffrey Davis,[8] an Australian physician affiliated with the International Abortion Research and Training Centre in London.

[14] PSI is one of a select group of charities endorsed by noted philosopher and Princeton Professor Peter Singer as Highly Effective in the fight against extreme poverty.

In 2007 and 2008 PSI was highlighted by Fast Company[19] as a Top Social Capitalist, noting the organization's private sector partnerships with Procter & Gamble and others.