Please view this IRS document as this explains how this income should be reported. In the document, it explains the reporting requirements if the child's investment income is over $2300. in this case, a 8615 would need to be filed. Turbo Tax can handle this if needed
If your child's investment income is less than $11,500 you may include this income on your own return by filing a 8814. Trubo Tax can handle this filing also. Certain other conditions must apply for the income to be included in your. Please read the additional requirements in the link provided above.