Even though sociobiology never became vogue exactly, many biologists eventually warmed up to the ideas, albeit tweaking and interpreting them in a new and modern way. For Wilson, love was bound up in sex and altruistic behavior. For his scientific siblings, it may be bound up in histones and DNA.

And then there are those who believe love to be spiritual, mysterious and bound up in something not nearly as concrete as genes. For the deeply religious, like my mother, love is a ruling aspect of our lives, meant to guide us on the path of righteousness. For them it is a unifying thread for all humanity, binding us all in its sticky web. My mother believes that children are born with love like they are born with God. She could be right or she could be in what I call a state of biological denial. My mother, like most people, may not want to accept the idea that what she feels so strongly for her children and what her children feel for her are caused by proteins, synaptic firings and bodily fluids.

A friend of mine is of the opinion that a child's love does not exist at all. (Nor does it blossom between two unrelated persons, according to her.) She thinks a child's love is an emotional attachment, and there is some truth to this. Parents act as anchor and stability in a world that must seem very large and very chaotic to a newborn child. Caregivers are the first to give security and comfort -- and they are loved for it. Later on, many of us will find new "love" attachments, with religion, work, a family of our own or even a bowl of soup. For my friend, maternal affection is the only true expression of love. But if you combine her opinion with Wilson's theory, then no love remains at all, and this is a disheartening thought.

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Perhaps novelist Haruki Murakami has found the key. In his short fiction "Man-Eating Cats," he describes an adulterous affair not in terms of mere love but as total and complete empathy. Murakami implies that when we say "I love you," we mean "I empathize."

And this makes sense. The child who is with his or her mother day and night for months and months would eventually have to identify emotionally with that mother. It is entirely possible that, as humans, we may empathize more than we love, truly understanding what others are going through in this life, the unbearable weightiness of mere existence.

If this is true, then love need not prevail in evolution or religion or nonexistence. Perfect understanding is, well, more understandable and intuitively grasped than the idea of love. We can "get" someone much easier than we can love them. We can define "my understanding" better than we can define "my love." So love need not exist at all.

Still, I want to hear my son say it, whether or not he can define it or clarify its origins. They haven't found a gene for love or even begun looking for one as far as I can tell, but part of me hopes that they will. This is the only thing that gives me solace on those long, fussy days, when I question the why and what of this new journey I have undertaken. Rather than delve into the chapter on "Parental Care" or "Group Selection and Altruism" in Wilson's text, I'd rather rest my mind on this thought: He has to love me; it's in his genes.

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