One former child-related opportunity to lower your tax bill, however, has been dramatically reduced. Previously, many parents shifted some of their higher-taxed investment income to their young children so that the earnings would be taxed at a lower bracket; for example, falling from a possible 35 percent rate to the youngsters' usually 10 percent or 15 percent bracket.

But the so-called kiddie tax limits this practice. When a young investor's 2011 or 2012 earnings exceed $1,900, the tax rate applied to those excess earnings is the parents' -- not the child's. The higher tax rate remains in place until the child turns 19 or age 24 if the young investor is a full-time student.

So, Mom and Dad, keep an eye on young Jimmy's or Jane's assets because you could be paying the taxes on them.