In 46 years since the first human couple relied on IVF to conceive a child, the procedure has become the principle tool of assisted reproduction. Some religions embrace it enthusiastically for couples who would otherwise be childless. Others tolerate it but may impose restrictions on how the procedure is practiced and who can benefit from it. A few religions condemn IVF and urge their infertile adherents to forego it. The wide range of religious attitudes about IVF reflect how the human embryo is viewed with regard to the inception of personhood and when ensoulment occurs. These are philosophical concepts that science can neither prove nor refute. This article discusses dominant themes that have emerged in determining how different religions view IVF.