The dilemma I’m facing a difficult situation with my retired parents and two young children. When I had my first child my parents doted on him, but since my second they’ve transferred their affection and patience to my daughter. While they’ll happily indulge her – even her tantrums – they now have little time for their older grandchild and bat away his frequent requests to play with him, preferring to scroll on their phones or read the papers.

Our son has picked up on the disparity and has started acting up whenever they come to stay. They expect impeccable behaviour from him and are quick to tell him off in a shaming way that I’m not comfortable with. I did raise this once on a never-to-be-repeated family holiday last year, reminding them both that he was very little, but was met with total silence.

After that my husband and I decided to change the way future visits were managed, to make sure our son wasn’t ignored or told off unnecessarily. My parents keep offering to look after the kids and they’re sounding increasingly offended every time I assure them we’ve got it covered. It would actually be really helpful to have the childcare, but I can’t expose the kids to their grandparents’ unfair treatment. How do I handle this?

Mariella replies Maybe try not to. That isn’t a licence to abandon all sense of reason; rather an encouragement to employ some. Excuse me for being blunt but it does sound like a problem that’s partly self-created. I’m sure that’s not what you want to hear and, in your shoes, ones I’ve worn on many an occasion, I’m not surprised. No one likes to have the finger of blame pointed at them and when it comes to family matters our skins are particularly thin. Emotional dynamics set in childhood are often what inform our familial relationships to our dying day. A determination not to delve beneath the surface is nothing to be proud of. Truth is… life’s unfair. I daresay that’s a salient fact you won’t be unaware of, but it does seem timely to reiterate it.

A new baby is often the focus of attention, singled out, adored, favoured and then, as they mature into terrible two-year-olds, cast out of the spotlight. My daughter was so unimpressed with the arrival of her brother 13 months later, in particular his unique appeal to “her” parents, grandparents and a miscellany of visitors, that she projectile vomited for the first 24 hours of his presence in the house. Thankfully they are now the firmest of friends, although she never shies away from pointing out his less savoury habits. It’s a detail I share with you only to establish how universal the impulse to adore a newborn is and how swiftly that moment will pass.

When it comes to family matters our skins are very thin

It’s a sad day when grandparents’ visits need to be “managed”, and while I am immensely sympathetic to the complications of extended family life – and the words “never to be repeated family holiday” will resound with many – I’m still not sure about such a prescriptive approach. Your parents are doing what comes naturally to them and I’d be tempted to enjoy it while it lasts and use their spotlight on your daughter to allow you a little extra bonding time with your boy.

Issues around discipline will always prove incendiary and although it’s worth initiating a discussion to agree a universal approach, the likelihood of long-term consensus is slim to zero. In my case, refusing my children sweets when they were young merely offered their grandparents an open goal which they stuffed with Haribo, Maltesers and the like. Once I gave up trying to police it, I just sat back and admired their ability to grab whatever advantage they could to earn themselves adoration and devotion!

That said, if it becomes an ordeal, you may wonder if it’s worth the bother. To what degree should we protect our children from what life throws at them? I worry that our determination to keep them in our protective forcefield hinders their ability to deal with life’s vagaries later on. Seventies parenting is much mocked, but it certainly prepared us for the rough and tumble of what was to come. Now we’re better informed, more psychologically tuned in, and increasingly aware of the dangers that lie beyond our protection zone, we are also far less likely to let them brush up against pain, physical or mental, without a protective arm involuntarily shooting out to block or stall it. I’ve no doubt your parents love both grandchildren equally but right now they’re predictably in thrall to the lure of the new.

My advice is to try to step back, let these relationships take their course and only step in when there’s potential jeopardy involved. The more your children learn about the complicated nature of humanity, the better they’ll be able to cope when you can no longer build a Berlin Wall around them. The hardest thing about being a parent is learning to let go and it’s a heartbreaking process that begins the moment they emerge from the safety of your womb.

If you have a dilemma, send a brief email to mariella.frostrup@observer.co.uk. Follow her on Twitter @mariellaf1