ForeignersChildrenInChinaStatus
http://gocn.southcn.com/qzfg/dfxfg/200604050014.htm
广州市人口与计划生育管理办法
2006-04-05 16:45:52
第十六条 本市户籍居民到国外或者港澳台地区工作、旅游、探亲、留学期间生育的子女取得外国或者港澳台居留权的，不计入家庭子女数；入本市户籍的，计入家庭子女数。
According to this, children born to Chinese abroad who get foreign nationality are not counted for population planning purposes.