Ofcourse men with small children should also be okay as long as they do not have a woman with them since in Western countries, you can never be sure whether the male and female are married. Better to ask for their marriage license before allowing them to get into the taxi just to be sure. I guess even transporting two males might be a bit problematic since they could actually turn out to be gays. Therefore, the best bet would be to allow only one male to transported in the taxi.