I heard a sad story the other day about a woman in her early 60s who had spent her whole life feeling insecure about her mother's love.
There was no big falling out but she'd always felt that her sister was the favourite one.
Recently her mother died and left everything – house, money, jewellery – to the other sister.
The woman is heartbroken to be cut out of the will because it feels like final confirmation that her mother never loved her.
Both sisters are married and well off, so it's more about the emotional significance than the money.
This is why inheritance is such a loaded topic – it's rarely just about the money. Sibling rivalry and feelings of love and rejection make it an ethical and emotional minefield.
I spoke to Simon Longstaff, the executive director of the Ethics Centre, about the ethics of treating your children differently in your will.
This is separate to the legal question. If someone makes a claim on the will, the courts will look at how the person is related to the will writer, and their financial need. There's no legal obligation to treat children equally, but it's best to consult a solicitor about your plans.
Even so, estate planning can be tricky, especially if there are second marriages and step-children or half-siblings involved. Some people put it in the too-hard basket, while others attempt to rule from the grave.
On the ethical question, Dr Longstaff distinguishes between assets passed down through a family, such as heirloom jewellery, and wealth that you've accumulated during your lifetime purely through your own work and efforts.
Legally, you might be entitled to dispose of an heirloom however you like, either during your lifetime or in your will. But Dr Longstaff argues that ethically you cannot, if you accepted it knowing you were expected to keep it in trust for the next generation.
For self-made wealth, Dr Longstaff says there is no moral duty to pass it on to your children at all, nor to pass it on equally.
However, he adds that duty is just one aspect of ethical decision making. There's also the question of character – that is, if your decision is consistent with your own values – and then there are consequences.
Dr Longstaff says consequences are a huge part of estate planning.
A utilitarian approach would look at the rational consequences of where the money would be the greatest use.
Maybe one child would spend it more wisely than another. Maybe there's greater or lesser need – if one child has a disability and needs more money for ongoing care, or you have a lottery winner in the family.
If none of your children need the money, perhaps you want to give it to charity, or skip straight to your grandchildren. Then again, maybe you don't want to give it to your grandchildren because a large inheritance at a young age would be radically life-changing.
There are also emotional consequences.
If you play favourites in your will, the consequence might be that someone winds up feeling hurt or unloved at a time of grief. Or even that your children wind up fighting one another. Sometimes people would rather the lawyers got the money than a hated sibling.
Dr Longstaff mentioned one man with several children who kept a ledger of every gift or loan of money he ever gave them, with the intention of equalising it all in his estate. He eventually scrapped that approach because although scrupulously fair, it felt cold and calculated, and he worried it would be misconstrued by his children.
Sometimes people want to reward the child who looked after them in their old age, but Dr Longstaff cautions this may not be fair if the other children had responsibilities of their own.
He says most families would understand if parents left more money to provide for a disabled child. It might be argued they're providing equality of life opportunity for all their children, but the cost happens to be different for each individual.
If you have good reasons not to divide the estate equally, but you care about the consequences, then it is wise to have the conversations with everyone concerned while you're still alive.
I feel lucky my affairs are simple.
This article was originally published by the Sydney Morning Herald on 27 July 2016. It represents the views of the author only and does not necessarily reflect the views of AMP.
Making a will
Our short online learning module explains why a will is important and how to ensure your money ends up in the right hands.
If you’re going in to negotiate your salary, it’s important you know what to say and what not to say.