The couples gathered for this Mass with Pope Francis knew a thing or two about marriage, since they were celebrating their 25th, 50th or 60th wedding anniversaries.

Still, the pope delivered a blunt homily on a painful family issue. The bottom line: Many Catholics do not want children.

"There are things that Jesus doesn't like," said Francis, in a 2014 service at the Vatican guesthouse he calls home. For example, there are parents who simply "want to be without fruitfulness."

Today's "culture of well-being," he said, has "convinced us that it's better to not have children! It's better. That way you can see the world, be on vacation. You can have a fancy home in the country. You'll be carefree." Apparently, many Catholics think it's easier to "have a puppy, two cats, and the love goes to the two cats and the puppy. … Have you seen this?"

Yes, Catholic leaders can see that reality in their pews and they know falling birth rates are linked to many sobering trends, from parochial-school closings to once-thriving parishes needing sell their sanctuaries.

Then there is the annual survey from Georgetown University's Center for Applied Research in the Apostolate (CARA) reporting the number of men poised to be ordained as Catholic priests in the United States.

The class of 2018 is expected to be 430, and 25 percent of those men were foreign-born.

It's an often quoted fact: The number of men ordained each year is about a third of what's needed to replace priests who are retiring, dying or simply leaving. Two decades ago it was common to see between 800 and 900 ordinations a year.

Birth rates are the "overlooked factor in all of this," said sociologist Anne Hendershott, who leads the Veritas Center for Ethics in Public Life at Franciscan University of Steubenville, Ohio. "It's kind of difficult to talk about this, because Catholic families used to be huge, which meant parents were willing to give up a son who wanted to enter the priesthood. Things have changed, obviously."

Catholic families in America are shrinking. Catholic parents of Baby Boomers had about 3.5 children, according to charts on a CARA research blog. In recent decades that number has declined to 2.2 or 2.3 -- just above the 2.1 "replacement" birth rate in America. Meanwhile, 2017 data from the Centers for Disease Control and Prevention cited a 1.77 national fertility rate.

In the new CARA survey, only 4 percent of the ordinands reported being an only child, while half said they had three siblings or more. About a quarter of the men said they were the youngest child in their families.

Other symbolic trends among the ordinands included:

* One in three said they have a relative who is a priest, monk or nun.

* Half said that one or more people -- usually friends or family members -- discouraged them from considering the priesthood.

* Nearly half received a college degree before entering seminary, with the most common majors being liberal arts, social science, philosophy, theology or business.

Another trend worth watching, said Hendershott, is the impact of homeschooling families, which often include more children than the norm. A new Seton Magazine report noted that 30 percent of Diocese of Arlington (Va.) seminarians are from homeschooling families. At Philadelphia's St. Charles Borromeo Seminary 10 of the school's 47 students were homeschooled. There are 100,000 Catholic homeschool students in America, compared to 2 million in Catholic schools.

Hendershott said that her own research suggests that a pivotal factor in recruiting priests is whether parents believe their bishops are trustworthy, in terms of defending core Catholic teachings -- especially on hot issues linked to sexuality, marriage and the family. A bishop needs to be "pro-life," in every sense of the word. Doctrine often affects demographics.

"Catholic mothers will give up their sons if they trust their bishop and truly believe he will protect their son and faithfully support his ministry," she said. "Catholics have to study the data and pay close attention to the records of their bishops, in terms of inspiring men to become priests.

"Look at what's happening in Lincoln, Nebraska. Look at the Diocese of Arlington. There are dioceses where the bishop gets it, and those where he doesn't. … Look for the dioceses that have lots of life."