Eleven years in a Christian Brothers school, so keep your condescension. Obviously if the marriage were never valid, as per marrying your sister, what I said wouldn't hold. But we were instructed that the standard reasons for annulment would generally not be found valid if people had been married for an extended length of time, had clearly consummated the marriage, and had children.
I suspect the difference here is between practice in America compared with Ireland, where I grew up.
What condescension? It was Abp. Fulton Sheen who said that Catholic parents who wanted their children to lose their faith should send them to a Catholic school. (He was speaking specifically about colleges, but the rot has spread since then.)
I long ago gave up trusting the Catholic Church (at the local level) to teach Catholicism. Sometimes it happens, but not reliably.
It ain't condescension, pal -- it's realism.
But we were instructed that the standard reasons for annulment would generally not be found valid if people had been married for an extended length of time, had clearly consummated the marriage, and had children.
That's a huge gloss, because none of those things ipso facto have anything to do with it. The issues are (1) whether the people in question are qualified to marry, and qualified to marry each other; (2) whether they are married according to canonical form; and (3) whether the consent they gave was informed, free, and complete.
IOW, a man who contracted marriage with the well-formed intention at the time of the ceremony to cheat on his wife would not be married. His vows were a lie. This would be the case even if he stayed (legally) married to his wife for 30 years and sired a small herd of children by her.
I suspect the difference here is between practice in America compared with Ireland, where I grew up.
I do not dispute the accusation that annullment practice in the USA is frequently or always lax. I'm merely disputing your claim that having children has any substantial relationship to the question of whether a marriage is null and void in the eyes of the Church.