If a child has gross income greater than $1100 but less than $12,500, is a tax return required?

It depends on the type of income the child received.  Was this from self-employment income?  Was this from wages received as an employ on a W-2?  What amount was unearned income, interest, dividends, capital gains?

If your child's gross income is only earned income, he/she must file a return if the gross income is more than $12550.

If the child gross income is only unearned income, he/she must file a return if the gross income is more than $1100.

If the child has earned and unearned , he/she needs to file if earned and unearned income together totals more than the larger of (1) $1,100, or (2) total earned income (up to $12,200) plus $350.