If you then add all the other systems, then you will sometimes be awed by the complexity of human coexistence.

Yes, it is far much more complicated than we even imagine. Too many factors play a role.

In my first steady relationship, I was with a man who was himself the youngest child of two older sisters. That didn't really fit.

It is funny that you say that because later in his book Toman examines the marriage and family outcomes depending on the birth order of the partners/ parents.

I did not know him yet and I am happy to have received a new name from you.

I wasn't familiar with him, too. I found his work by accident and he really got my attention. It turns out that he is an author of poems, novels, and prose, in which he talks about social delusions (according to wiki).