Your question assumes, of course, that it was easier to remain celibate during, say, the twelfth century than it is now. Be that as it may, the Catholic Church's requirement of a celibate priesthood is a matter of discipline, not doctrine. Our sister churches among the Eastern Orthodox (and indeed the Eastern-rite branches of Catholicism) allow a married priesthood, although the priest must marry before he is ordained, and no married man may become a bishop. Married Anglican priests who enter the Church of Rome may keep their wives on re-ordination as Catholic priests. Yet even in the Eastern churches, celibacy for clerics is held in high esteem--because Christ himself never married and praised virginity.
The Western Church has a strong and ancient tradition, dating back to the Council of Elvira in the early fourth century, of celibacy as the norm for its priesthood. Pope Gregory VII (r. 1073-1085) made celibacy mandatory as part of his effort to wrest the church from lay control, and the Second Lateran Council of 1139 confirmed this rule of mandatory celibacy. The church remains free to change this mandate should circumstances warrant, although it is highly unlikely to do so in the near future. The practical problem of supporting not only priests but their families is a serious one. Furthermore, in a culture that embraces easy divorce, even for members of the clergy, not to mention other forms of nonmarital sex, easing the requirement of mandatory celibacy for priests at this time would probably create as many problems as it would solve.
Is it true that Pope John Paul had a son? If so, who is he? Who was his mother?
Although I've heard that young Karol Wojtyla, who was handsome and athletic, had a girlfriend, the Polish actress Halina Krolikiewicz, with whom he, a fellow actor, was very close friends before he entered the priesthood, I've never heard anything about a son. So I just can't verify this rumor.
What is the ranking order of the church hierarchy below the pope?
Below the pope come bishops, then priests. Bishops of large, major cities are known as archbishops, but they have no authority over other bishops or priests, except for the assistant bishops and priests in their own dioceses. Cardinals are usually bishops, but, like archbishops, they have no power over other bishops. They do have certain powers not available to ordinary bishops, such as electing the next pope.
I know some Catholic women in the U.S., would like the ordination of women priests. Is this likely to happen?
The Catholic Church is highly unlikely to alter the rule banning women from priestly ordination.
How do I become a Catholic? I believe in Jesus, have been saved, and I was confirmed an Anglican.
I suggest contacting a Catholic priest. If you know a priest, he will undoubtedly be delighted to help you, but if even if you don't, just call a nearby Catholic parish office. As an Anglican, you don't have to be rebaptized in order to enter the Catholic Church, but you do have to undergo a formal rite of reception into the church. In most places, these rites take place at the Easter Vigil service. For literature about Catholicism, I suggest visiting a Catholic bookstore (the Daughters of St. Paul operate excellent stores, and so does Opus Dei). I recommend reading Marcellino D'Ambrosio's "Exploring the Catholic Church: An Introduction to Catholic Teaching and Practice."
Does the Catholic Church believe in the Holy Spirit? Did Pope John Paul II ever preach about the Holy Spirit?
Yes, the Catholic Church definitely believes in the Holy Spirit as co-equal with God the Father and Jesus Christ the Son. Catholics celebrate the feast of Pentecost, when the Holy Spirit descended upon the apostles, giving birth to the church. In 1986 John Paul II wrote an encylical, "Dominum et Vivificantem," celebrating the life of the Holy Spirit in the church.