最佳答案：

家人的复数是families。

造句有：

1、With today more efficient contraception women can plan their families and careers.

如今有了更加有效的避孕方法，女性便可以规划她们的家庭和事业。

2、I think it is very rare to have big families nowadays.

我想，如今大家庭已经很少见了。