The US study reported a 34% reduction in a combined measure of alcohol, tobacco and cannabis use among boys, plus significant benefits regarding condom use, frequency of sex, iolence and truancy.

• 美国的研究显示，在男孩子中饮酒、吸烟和吸食大麻综合测量结果下降了34%25，在应用安全套、性交频率、暴力和堕胎方面有明显改善。