The research team examined data from the UK Millennium Cohort Study, which records health data for thousands of children born between 2000 and 2002. Among the goals of the study is to collect information on fathers' involvement in children's care and development. After a first survey of the children at 9 months old, surveys collected information for each child at ages 3, 5, 7 and 11 years old.
Overall, the researchers examined the records of nearly 11,000 children. Of these thousands of children, more than a quarter had experienced the absence of a biological parent by age 7.

في الإجمال فحص الباحثون سجلات 11000 طفل ومن هذا المجموع وجد ان حوالي ربع الاطفال قد اختبروا مسالة غياب الاب قبل سن السابعة

During their age-11 survey, the children were asked whether they had ever smoked cigarettes or drunk alcohol. Those who had tried booze also answered whether they'd had enough to feel drunk