Sleepless nights caused by a crying baby are blamed by  parents for the breakdown of up to a third of relationships, research shows. Parents with a young child get about six hours sleep a night, an hour less than is recommended. Experts also say that adults need at least five hours’ uninterrupted sleep to be able to function and concentrate properly the next day. A survey of 2,000 parents found that 30 per cent of those who had divorced or separated blamed sleepless or interrupted nights caused by their children. Eleven per cent admitted pretending to be asleep when their child woke up so their partner would have to deal with them. Another 11 per cent said they shut the door to block out the noise while 9 per cent turned up the television. One in 20 said they had become so tired they had fallen asleep behind the wheel. Psychologist Tanya Byron, who appears on the show, said: ‘I see people whose children have chronic sleep problems and they’ll say things like their children get really upset if they try to send them to bed. ‘Well, I promise you, they won’t hate you in the morning when they’ve had a proper rest. ‘Our generation struggles  with discipline much more than any other, but the lack of boundaries will only cause more and more difficulties. ‘From a clinical perspective, a lot of those I see in my own  clinics, predominantly children, have underlying issues with not getting enough sleep, even if that isn’t the problem they are presenting with. ‘Behavioural difficulties, family issues, learning and concentration issues: there is a significant number of these common problems which have poor sleep at the heart of it.’ Recent research by US scientists showed that a good night’s sleep improved a couple’s relationship by making them less selfish. The academics, from the University of Berkeley, California, found that couples who slept well were more likely to be polite to each other.