If ɧoɱosɛҳųαƖs are unsuitable to be priests, then how are they suitable to be husbands and fathers of children?

It depends if they were an outright, practicing homo or just someone with inclinations and effeminacy.  These types of people, either way, are unsuitable for both priesthood and marriage, but...someone who has just "inclinations" is not necessarily prohibited from these sacraments.  What I mean is that such inclinations/temptations aren't impediments, sacramentally speaking.  Though we all know, in practice, these traits are a disaster.  That's why you prepare in seminary for 6 years and why you date - to be on the lookout for timebombs.

I would imagine, if it is grounds, it would be based on hiding a material fact from the spouse which is critical to the primary purpose of marriage. 

If he were a practicing homo before and after marriage, then probably grounds since he didn't have any intention to be faithful.  But if he did want to stay faithful, but she just found out about his inclinations later, even if he had cheated on her, then I don't see how it could be annulled.  A seminarian in the same situation would be a valid priest, it's just that in former days, were his inclinations to be found out, he'd be "retired" to either an ecclesiastical prison or a monastery on some island.

 Much like a man who lied about being a baptised Catholic got married on that basis and then later admitted he was a fraud.

That's different, because it's a noted impediment to marriage.

Let's imagine a man was a convicted paedophile got out of jail and hid that from his future wife.  Surely that would be ground for an annulment.  He hoodwinked her.  As I understand it you cannot hoodwink a person into marriage.

As bad as that is, immorality isn't an impediment to marriage.  Prayer and due diligence would have these items surface before marriage, as God has promised.

Due diligence?

Who here ran their spouse through the criminal records bureau for a check before marrying them?

My wife told me she was doing a PhD and working for LukOil.   I believed her.

If she was a skilled con-artist she could easily have hoodwinked me.

People get conned all the time, because we operate on trust.  We only check people out when we have good reasons to be suspicious.

Due diligence would mean, for marriage, to have all kinds of discussions while dating about all types of topics, meeting their family, friends, etc (as we've discussed previously).  Then there's spiritual due diligence where you pray and ask God to show you why this person is/isn't for you.  Most people let their emotions control the show, as Elvis sang "...Only fools rush in..."

In the above case his parents knew he was a homo...So he must have known too.

Sorry, I missed this part.  Certainly this would make a compelling case for annulment.  

If a skilled deceiver wants to deceive you then the chances are they can.  Pre-internet it was even easier.

I agree with you, on the natural level, which is why you pray.  I firmly believe, without a shadow of a doubt, that if one approaches dating with an open heart to God's will, with prayer and patience, and a desire to find a spouse that will help you to get to heaven, God will answer you.

As I understand it, you were either validly married on the day or not.  If not, you are no more married than an unmarried person.  The tribunal looks at the circuмstances and behavior in your marriage to determine the likely state of mind up to and on the day of your wedding.  They cannot ever know for certain they just work on the balance of probabilites like any legal judgement.

A man could have a child or many children with a live in girlfriend of 10 years and be free to marry if he leaves her.  A woman could have illegitemate children from many different men and be free to marry.

A priest who had abandonned his vocation could have a wedding have 7 children and would not be married.  That is the nature of the sacramental bond. It either exists or it does not.

The marriage is determined to have never been real in the first place.  Therefore pragmatic considerations such as the welfare of children should not be part of that decisioning process or if they are, ONLY, in the sense that they give evidence to the state of mind up to and on the wedding day.

This is why it is ridiculous for Mel Gibson or Bud MacFarlane Jr to apply for or consider an annulment.  Because their married life suggests they were completely married.

Someone in a sexless marriage, however, suggests they (one or both) have no clue what marriage is about, its PRIMARY purpose.  One child being born because his wife agreed to sex for one night, and then went back to refusing sex would demonstrate a completely perverted understanding of the duties of marriage.

I wonder what would happen if the Church banned annulments.  Simply said, approach marriage with extreme caution and if it all goes horribly wrong there is no safety net.

Plenty of people would of course just civilly marry outside the Church.  I know lots of Trads who came back to the Church age 60+ after their glory days were behind them or their partner dies.  Matthew discusses such a couple above.

People would probably get married a lot later.

Would there be a lot more engagements broken off?

There is no safety net for Hell after all.  You find yourself there and you are burning for all eternity.

The past had very different social mores and stigmas.  Life was harder in general and people probably thought about their illnesses, death of friends or whether they would make it through the winter.  Wives regularly died and men who could afford to support another didn't find it difficult to find someone who needed a roof over their head.  Much the same in some poor countries today.  Just saw a docuмentary about poor Chinese farmers importing Indonesian peasant women to marry.

I wonder what would happen if the Church banned annulments.  Simply said, approach marriage with extreme caution and if it all goes horribly wrong there is no safety net.

Well, they effectively WERE banned before Vatican II.  What, were there maybe a small handful of annulments granted every year worldwide ... apart from the cut-and-dry cases where it was found that the person had been in a prior marriage or something?  This nonsense about psychological impediments and "immaturity", etc. was not even entertained.  That's what the priest did in marriage preparation, made sure that the couple knew exactly what they were getting into so that by the time they said their vows they knew full well what it entailed.