al-Hamdu-Lillaahi Rabbil-'Aalameen was-Salaatu was-Salaamu 'alaa Ashrafil-Anbiyaa'e wal-Mursaleen, wa ba'd:
As-Salaamu alaikum wa Rahmatullaah
How many times have you woken up for Fajr, rubbed your eyes and went in to your childrens room seen them sleeping and decided to try and wake them up with little success and then thought to yourself let them sleep. Even though the child is over the age of 10. Look at how the great Imaam of Sunnah used to do this.
Try it and see if it works. I can testify that it does.
Concerning the Imaam, the Shaykh - 'Abdul-'Azeez ibn Baaz (rahima-hullaah), his son Ahmad narrates:
"The Shaykh used to call his children via the internal phone to wake them up for Salaat al-Fajr.
And when he called them, he would recite the (authentic and recommended) supplication:
((al-Hamdu Lillaahil-lathee Ahyaanaa ba'da maa Amaatanaa wa ilayhin-nushoor))
(All praise is for Allaah who gave us life having taken it from us and unto Him is the resurrection)
...since they were overcome by sleep, he would ask them to repeat this supplication until he felt sure they had woken up!"
al-Imaam Ibn Baaz - duroos wa mawaaqif wa 'ibar - Page 71