This is a very personal examination of the role of parenthood, and examines it through the lens of 'identity'. Solomon describes two forms of identity - 'vertical', that which is transmitted from, and can be identified with, the parents, and 'horizontal' - that which significantly differs from the parent and has no mark of their influence. 
 What might be included in 'horizontal identity'? Deafness, dwarfism, schizophrenia, autism, Down syndrome, child prodigies, LGBT people, and so forth. Mental, physical, and psychological differences which are wildly variant from their parents. 
 In these thick seven hundred pages, Solomon conveys something like real empathy. He tells about their cultures, their lives, how parents love, how they crack under the strain, how they love or try to love despite this vast gulf of difference between them. He admits that his own prejudices have fallen away after this time of research, and he, too, finds something to love with the people he meets. 
 This book is not clinical or distant. It is not an exhibition, inviting you to gawk and judge at these people. It is personal, it shares the most intimate details. See little people telling stories about how they'd met, how difficult it is to hug sometimes. See children with Downs Syndrome who are the happiest and most cheerful in the world. Here, there are some autistic children who make music, and here are some who are mental infants in adult bodies, tearing at their parents in rage. See prodigies who are so far distant from their parents, or are shackled by them. See the woman in Rwanda who begs him, "How can I love my daughter more?", who was the result of rape - and in that question, she reveals her own love. He does not treat these differences as stigmas, nor does he romanticize them. It is this tender balance between the elation and despair which characterizes parenthood. 
 This oral history has its roots in the author's own life. His parents were extremely supportive with his dyslexia, but less so over his homosexuality. The author has experienced the spectrum of support himself, and has a closer perspective and is willing to really learn about other people. We see his journey form ostracism and self-hate, and it moves to marriage with children. 
 The book ends with this, and also an endnote about genetics testing and 'designer babies'. A curious paradox: some parents of these children, especially those with rare illness or difference would describe it as the defining moment of strength and change in their lives. However, others would also turn around and say that they would not wish to inflict this suffering on another person's child. 
 From someone who has been there: thank you.