Addressing Key Questions in Organoid Models: Who, Where, How, and Why?

Organoids are three-dimensional cellular structures designed to recreate the biological characteristics of the body’s native tissues and organs in vitro. There has been a recent surge in studies utilizing organoids due to their distinct advantages over traditional two-dimensional in vitro approaches. However, there is no consensus on how to define organoids. This literature review aims to clarify the concept of organoids and address the four fundamental questions pertaining to organoid models: (i) What constitutes organoids?—The cellular material. (ii) Where do organoids grow?—The extracellular scaffold. (iii) How are organoids maintained in vitro?—Via the culture media. (iv) Why are organoids suitable in vitro models?—They represent reproducible, stable, and scalable models for biological applications. Finally, this review provides an update on the organoid models employed within the female reproductive tract, underscoring their relevance in both basic biology and clinical applications.