Researchers have discovered that divorce is catching and spreads like a disease through families, work places and friends. The domino effect means that if an immediate friend or colleague splits up, your own chance of divorce increases by 75 per cent. Even the break-up of a friend-ofafriend's marriage boosts your chances of divorce by a third, scientists say. They believe that break-ups within friendship groups force couples to start questioning their own relationships. They say that a friend's divorce can also reduce the social stigma of splitting up, even when children are involved.