Dear Colleagues,

Mammalian fertilization and early embryonic development are highly orchestrated processes that establish the foundation for successful pregnancy and lifelong health. In recent years, advances in molecular biology, imaging technologies, and genome-wide analyses have provided new insights into the mechanisms that regulate gamete interaction, fertilization, and the earliest stages of embryogenesis. These discoveries have revealed complex regulatory networks involving cellular signaling, metabolic regulation, epigenetic remodeling, and dynamic changes in chromatin and gene expression.

This special issue, “Novel Aspects of Mammalian Early Embryo Development and Fertilization Mechanisms”, aims to highlight emerging concepts and cutting-edge research that deepen our understanding of these fundamental biological events. Topics of interest include, but are not limited to, sperm–egg recognition and fusion, mechanisms of oocyte activation, early embryonic decisions on cell fate , metabolic and epigenetic regulation during preimplantation development, and the impact of assisted reproductive technologies on embryonic physiology and developmental outcomes.

By bringing together contributions from diverse model systems and methodological approaches, this issue provides an integrative perspective on the molecular and cellular mechanisms governing fertilization and early development. We hope that these studies will stimulate new ideas and collaborations, ultimately advancing reproductive biology and improving reproductive medicine.

Satoshi Kishigami
Guest Editor