A new pet can bring joy to a home, but it can also create tension and changes to the family dynamic, writes Benedict Carey in today’s special animal issue of Science Times.

The nature of individual human-pet relationships varies widely, and only now are scientists beginning to characterize those differences, and their impact on the family. Pets alter not only a family’s routines, after all, but also its hierarchy, its social rhythm, its web of relationships. Several new lines of research help explain why this overall effect can be so comforting in some families, and a source of tension in others. The answers have very little to do with the pet.

Read the full report, “Emotional Power Broker of the Modern Family,” and submit your own family pet photo. And then please join the discussion below and tell us your own stories. How have pets changed your family dynamic?