I wasn't aware of UK-born mothers' increased fertility rate. However, I'll argue that even if the fertitily rate of immigrant mothers decreased, this can expla

I wasn't aware of UK-born mothers' increased fertility rate. However, I'll argue that even if the fertitily rate of immigrant mothers decreased, this can explain the data because if more immigrants came in, the average fertility rate goes up (given that immigrants' decreased rate is still quite a bit higher than UK-born).