This question is an eternal one, I think, and it has much to do with our trust of the unseen and the world beyond the scientific. A cold, completely objective analysis of love would involve discussion of hormones, including those that go along with sexual attraction. In the case of the love of a mother for her children, you could explain the bond away by saying that parental attachment is an evolutionary consequence, urging the adults of a species to protect their offspring and ensure the health of the next generation. The thing we call "love" could be all just a bunch of chemicals buzzing around in our brains and bloodstreams.
But... SO much of our culture, our longings, our religions, our very being is driven by the idea of Love with a capital L. And, for those who have felt it (or felt the acute pain losing a loved one), it is certainly "real" in some sense. It means something. Maybe it means everything? As logical as I try to be, I have to agree with C.S. Lewis inChronicles of Narnia,and the later J.K. Rowling in the Harry Potter series when they categorize love as the oldest and most powerful magic there is, capable of transcending us far beyond the apes we might otherwise be.
I guess the truth is, whether love is a chemical cocktail or something more, we're all gonna keep falling for each other... no matter what. :)