One of the things that I've found the most vexatious in my career as a
 parish priest is when parents stop coming to church with their children
 after the kids have received Confirmation.  Many times, of course, the 
parents stop coming, too.  It's as if some holy ticket has now been 
punched and that there are no more reasons to join in corporate worship,
 Gospel-centered community activity, or even the exploration and 
deepening of one's character and relationships.  There are no more 
reasons to be a Christian, apparently, which negates to gibberish all of
 the vows they promised at their Confirmation.
In other
 words, by having your child stand before the congregation and make 
sacred promises, and then enabling them never to have to live the vows, 
you've made them into a liar.  What will they do the next time they 
stand in public and make promises?  You know, like at their induction 
ceremony or wedding?  Will those vows be lies, too?
Understand,
 this is not about professional frustration on my part.  Rather, it's 
about a colossal sense of pity and, I freely confess, borderline 
contempt for parents who so badly manage the most important years of 
their kids' lives.  The parents actively choose to remove themselves and
 their children from any community of faith and self-excommunicate from 
the sacrament.  They give them a taste of religion during their 
childhood and then, just as their questions and their wonder begin to 
ripen, jerk it away from them.
Parents, you allow your children to become neutered Christians just when they're about to become interesting.
Now, I know the excuses:
1.  They have sports on Sunday mornings.
2.  We're very busy.
3.  It's hard to get them going on Sundays; I'm tired of fighting with them.
4.  There isn't much for their age group at church.
In response:
1. 
 Well, whose fault is that?  Speaking as a former coach, recreation 
commissioner, and parent of sporty kids, it's the parents who ultimately
 determine the parameters of any sports program.  If you let some coach 
or league official dictate a Sabbath-free life for your offspring, many 
times because the coach needs to feel a surge of self-importance and 
control, you've made the coward's choice.
Also, I 
dislike mentioning this, but the odds are 99.999% that your kid will 
never be more than ordinary at a sport, so put away those dreams of a 
luxury box for players' families in Foxboro or wherever.  When he or she
 is an adult and facing adult issues, that smelly jersey or those 
disreputable sneakers will not address them.  A foundation in faith 
will.
2.  I know you and, I hate to break it to you, but you're not busy.  
You're not even half as busy as my wife and I were when we were raising 
more children than you.  Raising them in a household of two
 clergy, I might add, when both of us could not take the day off nor be late for 
church.  You're not as busy as were my parents, my dad with three jobs 
and my mom with two; you are not as busy as grandparents were, running 
both a farm and a furniture-making business.
Also, what's your kid doing?  Reading Moby Dick?  If your kid can name at least two Kardashians, you aren't busy and neither are they.
3.  They learn that from you, so own it.  You can fix it, but I think it's more your problem than it is theirs.
4. 
 That's because they don't come to church.  If they did, they would be 
able to, like young adults anywhere on the planet,  organize with other 
young adults and actually do mature and appropriate things.  Sleeping 
late or playing with a smart phone just turns your offspring into a 
puzzlewit.