The Gordon Research Conference on Fertilization and Activation of Development started in 1974, and has met every other year since 1977, making 2013 the 20th of these conferences. This Gordon Research Conference addresses the biological phenomena - biochemical, biophysical, molecular, cellular, and physiological - that render the gametes "fertilization-competent," the central events of fertilization itself, and the transition into early embryonic development. As has been a tradition at this conference, the 2013 conference will integrate conserved mechanisms and approaches to these questions across a wide range of species. The study of other animal models has led in the recent past to new ways to manage human reproduction and in the near future these investigations will have direct relevance to problems related with infertility and contraception. The awarding of the 2010 Nobel Prize in Physiology or Medicine to Dr. Robert G. Edwards for the development of in vitro fertilization underscores the significance of this area of biology and biomedical research. The scientific program for the 2013 conference is diverse and has presentations on a wide array of species and by speakers at all career stages. It includes talks focusing in reproductive epigenetics; in sperm and oocyte maturational processes; in gamete competition and evolution; and also in those phenomena occurring during and after fertilization which mediate successful early embryogenesis. The keynote address will be presented by Masaru Okabe, PhD, who has pioneered the use of Knock out technology to analyze fertilization phenotypes. Dr. Okabe will present his work in fertilization and gamete biology from both historical and present perspectives. Added to our usual format, this 2013 conference will be the first to integrate an associated Gordon Research Seminar with the goal of providing a forum for graduate students and post-docs to present their work in the field of gamete research and fertilization.