10/06/2011 12:38 pm ET | Updated Dec 06, 2011

Is Financial Favoritism Ever a Good Idea?

Mark the date. October 2011, and people are finally raising one of the biggest parenting taboos there is: do parents play favorites among their kids? We can debate whether parental preferences are wired into our DNA, or if most of us just have different kinds of relationships with our various children, but one kind of favoritism is clearly damaging well past childhood, and can even ripple through generations of families. And that's when one sibling receives more financial help than the other.

The good news is, when it comes to money, most parents get tripped up and treat siblings unfairly during four life milestones. So whether your kid is twenty-five-months- or twenty-five-years-old, you can be aware of these flash points before they arise.

1. Paying For School
It's never a good idea to pay more of one child's tuition or living expenses for college or grad school. And remember, that includes things like cars, clothes, laptops and books.

If one goes in-state and the other to a private university, it's OK to account for the relative tuition discount, and maybe, help the in-state child out more for a graduate program later on, or ask the kid at Colgate to work part time to help cover costs. But be clear about how much money you have to spend on everyone's overall education, and that it's being split evenly in the long run.

Most of all, this is not the time to make judgments about your children's relative talents or chance of professional success. Your financial commitment should be based on your child being your child, not on the path he has chosen relative to his siblings.

2. Planning A Wedding
Despite all of the advances women have made, many people still believe it's customary for the bride's family to pick up the lion's share of the wedding tab. If this is the case in your home, and you've paid for your daughter's big day, make sure to offer your son and his wife something to make up the difference when it's their turn: a honeymoon or help with furniture for their new place.

It's also never wise to play favorites with your future daughter-in-laws: if you're throwing a shower for one, you've got to do it for the other. At the end of the day, this is about building a life-long relationship with your kid's family -- and you never know how things will turn out. I interviewed plenty of women who had rocky relationships with their mothers-in-law in the beginning, but became quite close a few years later.

3. Giving To Grandchildren
It's especially important to be fair when gifting to your grandchildren -- whether or not their parent is your son or daughter (mothers seem to have a tough time with this one!). Kids have a laser-eye for disparities, and financial differences can poison relationships among cousins for decades.

Be consistent from the get-go. Don't buy your daughter's entire nursery, and your daughter-in-law's diaper bag. And be fair about birthdays, holidays, even trips to the mall when you're visiting. Small stuff adds up. Children see pictures and talk. They'll feel hurt and confused that you got their cousin a new bracelet or bike even if you live closer to that child and end up running more errands with them. In the age of online shopping, it's easy to send everyone something special from Grandma and Grandpa.

And it absolutely does not matter if one child is better off than the other, or how wealthy you think their spouse might be. Here, too, you're spending money on your grandchildren based on their status as your grandchild. Besides, household balance sheets are a complicated mix of choice and circumstance, and impossible to assess accurately from the outside, even for your son or daughter.

4. Writing Your Will
When it comes to estate planning, I believe all children and grandchildren should be treated, as my mom says, Even Steven -- no matter who makes what, or which kids come from your first or second marriage.

The last thing any parent wants to leave is a legacy of bad blood and jealousy. Your will is not the time to reward (or penalize) your children or grandchildren for the career they did or didn't have, where they decided to live, the size of their family, or the person they chose to marry.

There are, however, two major exceptions. When one sibling has a special need or a family member has suffered a tragic event, parents may want to leave more money or a trust fund to protect that child at the expense of brothers or sisters.

For instance, if one of your children (or grandchildren) has a mental or physical illness that prevents them from living independently as an adult, or one set of grandchildren has lost their family's primary earner, you should always feel comfortable adjusting your will accordingly, and provide them with the long-term care and support they'll need after you're gone.