Why did they start using FBS and FCS?

Fetal Bovine Serum (FBS) and Fetal Calf Serum (FCS) are used in cell culture and laboratory settings primarily for their rich nutrient content, which supports the growth and maintenance of various cell lines. They provide essential growth factors, hormones, and proteins that facilitate cellular proliferation and differentiation. Their use became prevalent due to their effectiveness in promoting cell viability and the reproducibility of experimental results in research and biomanufacturing. Additionally, FBS and FCS are relatively easy to obtain and handle, making them standard supplements in many biological experiments.