Refunds of federal income taxes are never taxable because the taxes were not deductible. Refunds of state income taxes may or may not be deductible. It depends on whether the taxpayer itemized deductions and whether the taxes that are refunded produced a tax benefit on the earlier return. Those who claim the standard deduction are never taxed on refunds of state income taxes; those who itemize may or may not have taxable income from the refund.
The tax on the investment income in excess of $1,700 (may change after 2007) of a child under age 18, based on the parents’ marginal tax rate and computed on Form 8615.