Psychologist Penelope Leach, whose parenting books have sold millions, has caused controversy by claiming that there's evidence that separation from their mothers "reduces brain development" and might give rise to "unhealthy attachment issues". Do other parenting experts agree?
Oliver James trained as a clinical child psychologist and has worked as a writer, journalist, broadcaster and television producer and presenter
"Of course, this is good advice. All the evidence suggests that younger children should not be separated from their primary caregiver who, in the vast majority of cases, is the mother.
"If the child has a really strong attachment to both parents, there might be a case for exploring whether it really matters if they have sleep- overs at the father's. But in most cases, you should do nothing to disrupt the relationship with the primary caregiver. To do so can affect the child's brain development.
"I'm particularly glad Penny is taking aim at the family-law profession, where there is appalling ignorance about these effects on children. The Government has failed for decades to put this right, although I'm not surprised. The ruling elite frequently had poor early care themselves – it's why they are so motivated to get to the top.
"After the age of three, it becomes more debatable about whether children will be damaged by living between two homes and by the age of about six, I don't think it's a problem. I know fathers who have backed off until that time and I'd like to see a child-centric society where this is more normal."
Paula Hall is author of 'Help Your Children Cope with Your Divorce' and spokesperson for Relate.
"The suggestion that children can't have a sleepover at their own father's house is not just unfair and unhelpful, it's divisive for couples. Furthermore, parents carry a huge amount of guilt and anxiety around divorce and separation as it is, so why add to it?
"Single mums deserve a break. Who better for the child to go to than the father? Are we saying kids should never go to stay with grandparents either? And what about when mums are going into hospital or give birth to a second child? Are we saying the existing child is suddenly going to have attachment problems? Come on. This is scaremongering.
"What affects children the most is conflict, and to suggest children can't spend a night at their dad's can only create more conflict. The second key factor that can damage children following divorce or separation, according to research, is lack of access to the non-resident parent and again, this ban would only add to this lack of access."
Nick Woodall is an author and practitioner at The Family Separation Clinic
"It's no bad thing to highlight the impact on children of having to spend time in two homes. Children don't automatically adapt and, psychologically, it can be tiring for children to move every two or three days. With little children, it can be disruptive not to have basic things around them that give them comfort and to have different expectations of behaviour and even with tiny babies, we know that a change in washing powder can be disruptive because the house smells different.
"But it doesn't follow that children shouldn't spend nights with both parents. In fact, the latest research suggests there are no adverse effects on even young children doing this and that there are good reasons for it to happen, including helping them maintain strong bonds with both parents.
"It's a very outdated view of child attachment to suggest that the role of mum is the only one that really matters, particularly as things have changed so dramatically, with dads now spending far more time as hands-on dads."
Elizabeth O'Shea is a parenting specialist, an approved educator for the Parent Practice, London, an accredited coach for the Parent Gym, and runs parenting courses in deprived areas
"It's a bit like saying that a mother should never go out and allow dad to put the children to bed. If parents separate, the earlier a child can get used to staying with both mum and dad, the better. It is psychologically damaging to refuse to allow a child to have overnight stays with their dad and that every attempt should be made to allow them to see as much as possible of both mum and dad, with the child having two homes where they feel they belong. Children need to be allowed to have a childhood, free from having to choose between their parents.
"Children are adaptable and will adjust well to the change if their parents work out how to minimise conflict and help the children adapt to two homes – and if children are allowed to have a good relationship with both parents, free from guilt."