If I purchase a property in an underage dependent's name (son or daughter), and then sell it before they reach the age of majority, do I need to claim the capital gains (losses) on income tax if I already have a principal residence?
From what I've read: In Canada, for tax purposes, a family unit (i.e. you, your spouse, and your dependent children) can only claim one property as principal residence, for the purpose of claiming the principal residence capital gains exemption. So, you need to pick which property you'll be claiming as your principal residence for tax purposes, as only one home can be designated principal residence for any given year.
Therefore, I imagine that if you already have a principal residence, you would not be able to shelter another property from capital gains taxes simply by putting it in the name of your dependent minor – (and is that even possible?) I would guess that gains on the sale of that additional property would be subject to capital gains tax.
Finally, if you're talking about having your dependent minor children owning real-estate, I agree with montyloree that you ought to check with a professional – it sounds potentially complicated.
If you buy property for an underage individual in essence you own the property, you'll be liable for capital gains. It's best to check with a tax consultant for a more exact answer.