If they want large families, what they really need is to encourage women to marry in their early 20's.
Ding! You want more kids? Get women to marry earlier. No really. Its that simple. Unfortunately, education requirements in a modern economy and western culture have been pushing in the wrong direction. Women get married later now.....and as a result of waiting until its too late and their youth is gone, many dont get married at all and have zero kids. This is a disaster for society - and for them ultimately.