Taxpayers who have one or more children in their household may, under certain conditions, obtain a child tax reduction. The taxpayer is entitled to tax reduction for children who were part of the taxpayer's household during the tax year and who were at the beginning of the tax year:  under 21 years of age.  at least 21 years of age, provided that the children have continuously pursued full-time vocational education and training lasting more than one year. at least 21 years of age, receiving continued family allowance (infirm children)