A: Sibling

HAVING SIBLINGS COULD LEAD TO A HAPPIER RELATIONSHIP: The brothers or sisters that annoyed you as a child could actually be the reason you’ll have a happier romantic relationship as an adult. A new study from OhioStateUniversity researchers suggests that growing up with siblings lays the foundation for healthy relationships and may even reduce the likelihood of divorce. With each sibling — up to about seven — someone has, their probability of getting divorced is reduced by two percent, according to the research. The theory is that developing ways to handle sibling relationships amounts to lessons in adaptation that could help make a marriage work later on. The study also found that an only child was less likely to get married at all, with the odds of marrying increasing three percent with the addition of each sibling to a family.