Paul VI caved on birth control, ignoring the overwhelming vote of the commission that had studied the issue for years. The testimony of married couples was the turning point - bishops who joined the commission supporting the traditional teaching were convinced by hearing the voice of THE church, that the Holy Spirit was guiding them to a new understanding. By ignoring this, and giving in to preserving the status quo, Paul VI contributed strongly to the dramatic -  and continuiing to this day - hemorrage of educated adults from the church in the developed countries.  He also contributed to the reality that the institution  has been almost totally ignored when it comes to teachings about human sexuality, marriage, and women.  His cowardice in the face of pressure from Ottaviani and his cohorts was a disaster for the church. If the male celibates could get birth control so wrong, they were clearly not to be trusted for moral guidance in many of the areas of greatest concern to the laity.