Family Life Cycle (FLC) can be viewed from two perspective. One, from consumer behavior perspective that I learned in marketing and secondly, from medicine discipline perspective.
I think to lead a healthy life is an important part to become happy. So, it is meaningful to have knowledge about FLC from school of medicine.
Medical School of University of Michigan's article about FLC is worth reading. It discusses a human's life stages lucidly and incorporates idea like taking a third decision couples have to make which decision are not any two proposed by spouses.