The United States Conference of Catholic Bishops' Committee on Vocations defined the primary role of parents as providing "authentic witness to the importance of faith, prayer and service to others." The first step is to give children an awareness of the nature of a vocation (a calling from God). After that, the role of parents is one of inviting their sons to ask whether God might be calling them to priesthood.
Parents are crtitical in fostering a child's response to a call to priesthood. A parent's first and foremost responsibility is the work of praying for their sons, that they may live holy and devout Catholic lives. Additionally mothers and fathers ought to often discuss vocations, especailly priesthood and religious life. Parents must live so as to foster thier children's personal relationship with Jesus Christ, the High Priest. Ask your son, "have you ever thought about being a priest?"
The call to marriage and the call to preisthood have similarities. Talk to your sons about how you discovered God's purpose in your life. How did you know that you were called to marriage? What about your career? Do you regard your work as a calling or a way you strive for holiness? For example, if you are a teacher or a physician, do you believe that you are doing God's work by serving your students or patients as best you can? If it is appropriate, teach you children from your mistakes. What would you do differently? You don't need to have all the answers. Read with your sons stories of saints, men and women who gave everything of themselves to life and share the Gospel with the world. Introduce your sons to admirable priests that you know.
Point out qualities in your children that apply to priesthood. Affirm them! Tell them that you see the generosity that shines forth in situations ranging from helping a younger sibling with homework to sticking up for a classmate on the playground. Commend their leadership qualities and teach them that Church leadership is one of the ways a natural leader can give of himself.