Children - Love them or Leave them?

Lately there have a number of similar situations with people in my life and I just want to attempt to understand this phenomenon. How do you leave a child? What are your motives for doing so? How can any adult not care for/love children? I know these things happen all the time, and solely for my own personal interest, I'd like to know how. Please note that this is not about passing judgment on others, but only for my own personal growth and understanding. Please feel free to respond anonymously if you so desire. Thanks, Beth