Dear Joan,  

You have put your finger on a real problem. However, if we are going reflect on it, we must remember what we discover about God in Christ: the only 'punishment' God gives us for our sins is to send Christ to redeem us. So, rather than picture God actively punishing us for this sin, it would be more accurate to picture the loving Father (who did everything for us creating us and sending his Son to redeem us) shaking his head in sadness as we leave the source of living water and try to slake our thirst in the cracked cisterns of our cultural desert. It just won't work, we won't find there what we need and search for. It hurts him to see us try it, over and over again, despite the painful consequences.  

The usual connection made between the contraceptive mentality and a drop in vocations is this: it makes for fewer children, therefore parents are less willing to give up one for God. You will often hear people toss in here as well the reflection that with increased affluence parents no longer have to send sons off to the seminary to make ends meet. A very poor explanation.  

We have to remember that God's ordinary plan for the believing Catholic is that he receive his faith, the living example of how to live it, from his parents. A vocation is in most cases a great blessing and reward that God gives to a family, a wonderful seal of approval on the Christian marriage of select parents (though not every saintly couple is blessed with a vocation in the family). For that reason a couple that engage in any practice that they know is wrong are not is a position to pass onto their children the real essence of our faith which is loving obedience and trust in God. They are not giving God his place. They pass on to their children a skewed vision of reality and the faith - mostly self-centered. I think that is the problem.  

Here we see again that a vocation is not solely something that comes from on high, independently of our actions. God has an active part he wants us to play in fostering them. It is our responsibility. Our faith is a living thing - not a question of words, but of how we make our lives conform to those words... There is the challenge.  

Is preaching from the pulpit the answer? Partially. It has to be a preaching that issues not from the letter of the law, but from the priest's personal experience of God, his personal fidelity to God, his own integrity as a follower of Christ. That is what will give him the strength to preach this 'hard teaching', and what will move the hearts of those who listen to him.