Humans, like all species, are molded by evolution through natural selection. While evolution is fundamental to all biological processes, the critical phase for competition and selection is reproduction, which includes various stages from courtship and mating to fertilization and pregnancy. In humans, IVF (in vitro fertilization) is employed to support the inherently inefficient reproduction via intercourse, and the proportion of children born through IVF is increasing in several countries. While IVF serves as a significant aid for infertile patients, it also bypasses reproductive barriers and alters selection pressures. This comprehensive review outlines the systematic differences in selection pressures on reproductive cells, individuals, and populations between IVF and natural conception. For instance, at the cellular selection level, IVF favors sperm traits that are efficient swimmers over short distances, whereas natural conception prioritizes forward motility over longer distances. Similarly, a male with low sperm quality and a female who opts to delay her first childbirth to a later age can both enhance their reproductive success through IVF, compared to relying solely on natural reproduction. As delayed reproduction is a cultural trait, IVF enables cultural practices that may, in turn, influence human evolution. A central theme of this review is to discuss the interactive effects of biological and cultural traits in the context of IVF and how these factors together drive the increased demand for IVF. The purpose of this review is not to argue against IVF, which is undoubtedly a major medical advancement, but rather to examine IVF and human evolution from a broad perspective, including potential long-term impacts. Since IVF is a relatively recent technology, empirical data indicating its evolutionary effects on humans are limited. Overall, we argue that IVF facilitates the redirection of resources away from natural reproduction, as IVF bypasses some of the resource-intensive processes inherent in natural conception. Consequently, IVF sets the evolutionary stage for a human species that increasingly relies on and adapts to technological means of reproduction.
