Knowledge about typical development is of fundamental importance for understanding and promoting child health and development. We aimed to ascertain when healthy children in four culturally and linguistically different countries attain developmental milestones and to identify similarities and differences across sexes and countries.

中文翻译：

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四个国家从性别到出生到3岁儿童发展的异同：一项横断面的观察性研究。

关于典型发展的知识对于理解和促进儿童健康与发展至关重要。我们的目标是确定四个文化和语言不同的国家/地区的健康儿童何时达到发展里程碑，并确定性别和国家/地区之间的异同。