This book studies reasons behind the dramatic decline in total fertility rate (TFR), which has dropped to half of its previous levels. A major factor contributing to this trend is the widespread lack of recognition of fertility issues as a medical concern, compounded by insufficient societal awareness. To better understand the dynamics of human reproduction, this book identifies various factors that influence fertility, including the male and female reproductive systems, lifestyle choices, career demands, societal pressures, environmental factors, and personal habits (e.g., millennials). Central to this understanding is the collection of vast amounts of data, for which AI algorithms play a crucial role. The book studies how AI can help predict fertility outcomes by analyzing diverse datasets for both male and female populations. It also discusses the growing reliance on assisted reproductive technologies, despite their high costs and inconsistent success rates, and how AI can assist in predicting these success rates to ease the financial burden on patients. The primary goal of this book is to highlight how (explainable) AI can become a powerful tool in predicting human fertility. Ultimately, it aims at raising the global TFR and addressing the challenges posed by declining fertility rates around the world.