Large families are traditional in Gaza, with mothers having an average of four children -- making the fertility rate one of the highest in the world. While cultural and social practices influence the birth rate, many parents here say it's their national duty to keep the Palestinian population growing. Al Jazeera's Jane Ferguson reports from Gaza. Subscribe to our channel http://bit.ly/AJSubscribe Follow us on Twitter https://twitter.com/AJEnglish Find us on Facebook https://www.facebook.com/aljazeera Check our website: http://www.aljazeera.com/