They are the only people having children; I know few Americans that need a minivan (or anything with more than 2 seats).
The worst thing to do is import people. That puts even more pressure on the native population to not breed.
Yeah when my daughter had a baby 2 yrs ago, it was obvious hanging around the maternity dept that
1) most babies being born will grow up to be Democrat voters
2) most babies being born are being paid for by current Republican voters