Becoming a parent changes us for sure... but perhaps even more than you’d think! According to research in the Nature Reviews Immunology journal, the arrival of a baby profoundly changes the immune systems of new parents to make them more similar. In couples who live together and have a child, their immune systems showed 50% less variation than in other couples! The reason? Lack of sleep, stress and all the interesting smells that go with having a new baby around... oh, and love, of course!