The problem with this thread is that there are many responses, but not everyone is thinking with the Church. Therefore the responses are incomplete. As I always tell me students, my novices and my directees. “Think with the Church. Say only what the Church says. Do not add your opinions or take away from her words and you will not be confused.”
The Church says
2366 Fecundity is a gift, an end of marriage, for conjugal love naturally tends to be fruitful. A child does not come from outside as something added on to the mutual love of the spouses, but springs from the very heart of that mutual giving, as its fruit and fulfillment. So the Church, which is “on the side of life,” teaches that “it is necessary that each and every marriage act remain ordered per se to the procreation of human life.” "This particular doctrine, expounded on numerous occasions by the Magisterium, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act."
Observe, there are two parts to marriage that are inseparable, the unitive and the procreative. Marriage is not solely about either procreation or companionship. It is about both. Life is the natural fruit of unity. Just as the union between Christ and the Church bears fruit in charity, so too the union between husband and wife bears fruit.
Having said that, the Church recognizes that many couples are childless for reasons beyond their control. However, a couple entering into the marriage covenant must be capable of sexual intercourse. Without it, the marriage covenant is not consummated and the marriage does not take place. Christ gives himself to the Church in heart, mind and body. Without his physical death the new covenant would not have been consummated. The covenant required the engagement of the body. This is the difference between the Christian and the Gnostic.
To attempt a marriage without a body that can function is to begin something that cannot be fulfilled or consummated. This is not the same as those couples who have been married and over the passage of time something happens and they can no longer engage in sexual intercourse. This was a later circumstance.
It is important to clarify the situation of Joseph and Mary. At the time of Joseph and Mary’s marriage, our people did not know about the fullness of marriage. Christ had not been incarnate. The sacramental nature of marriage had not been revealed. Mary and Joseph were validly married, as are all people who marry within their faith. There is a difference between a valid marriage and a sacramental marriage. All sacramental marriages are valid. While all valid marriages are not sacramental.
The best advice that I can offer any Catholic when these questions come up is the same that I give to my novices. “Never give your answer. Never rely on your thoughts. Never trust your knowledge. Remember that your are poor. Always answer with the words of the Church. If you don’t know what the Church says, look it up.”
Fraternally,
Br. JR, OSF
…but mostly to God…
We need to pray for these people.