The income tax filing for your children can be very beneficial to them in the future. For the 2011 tax year, if your child has income of less than $10,527 there is no tax to pay. However, by producing an income tax return for your child, he/she will reap the benefit of creating RRSP contribution room which can be used in the future.
Also if your child is above the age of 18, they can be entitled to the GST/HST credit. The only way your child can profit from this is to produce an income tax return.
For more information on payment dates and how the GST/HST credit is calculated, visit http://www.cra-arc.gc.ca/bnfts/gsthst/fq_pymnts-eng.html
Source: Canada Revenue Agency http://www.cra-arc.gc.ca/menu-e.html
