One cannot even begin to understand the compassion, the emptying of self, the denial of self in what Christ did for us and for our salvation until he/she has become a parent.
Those are not my words, but the words of a priest.
We do not beget children merely because were biologically programmed to do so (even though we are), nor merely because of God's commands (though we are), nor because it's economically beneficial to society (though it is), nor because it prevents society from dieing out (though it does), but because as a husband and a wife are called to die to each other for Christ's sake as the martyrs did and is understood as a sacrament, so the begetting of a child brings us further along in that mystery--to die to self, to carry the cross and follow our Lord. There is suffering in having children, but great joy. And I can say this after being a parent for only one year.