tool for spreading its message: in addition to ccli.org, the url birthcontrol.org redirects to the organization's website. Systems taught While CCL strongly encourages use of their symptothermal method, they also teach mucus-only and temperature-only systems. In addition, their materials contain information on a calendar-based method and a proposal for a cervical-position-only system. CCL believes that by teaching all these methods, couples have more freedom in choosing the natural method with which they feel the most comfortable. CCL also teaches and promotes ecological breastfeeding, a stricter variant of LAM. Like LAM, ecological breastfeeding provides guidelines for identifying and extending the natural period of infertility caused by breastfeeding. The Seven Standards of ecological breastfeeding were developed by Sheila Kippley. The first edition of her book Breastfeeding and Natural Child Spacing was published in 1969. CCL was recognized as an authoritative source of information on breastfeeding amenorrhea in a magazine published by La Leche League, an international breastfeeding support organization. The popular fertility awareness writer Katie Singer has written about the important role Sheila Kippley and CCL have played in conducting and promoting research on lactational amenorrhea. See also Billings ovulation method Creighton Model FertilityCare System Fertility awareness Further reading Footnotes External links Couple to Couple League US home page Couple to Couple League in the UK home page Anti-contraception activists Non-profit organizations based in Cincinnati