As the opioid crisis has left nearly half a million children in need of homes, Catholic leaders are calling their families and parishes to a work of mercy that is both pro-life and fruitful: supporting vulnerable children in foster care.

"Foster care and adoption is another way that God is calling couples to be open to life, and not just infertile couples, but couples that have biological children who can welcome another child into their family," said Archbishop Joseph Naumann of Kansas City in Kansas at an event on foster care after the National Catholic Prayer Breakfast.

Kathryn Jean Lopez, who hosted the May 24 event titled "Fostering A Culture of Hope," told CNA she hopes it will get more Catholics around the country talking about foster care at a time when the opioid crisis has made it more urgent.

"It is key to our identity. We are adopted daughters and sons of the Father, and we shouldn't have orphans in our midst," said Lopez, who has written about pro-life issues for the National Review for two decades.

From 2000 to 2012, the number of babies born with neonatal abstinence syndrome, the withdrawal infants experience after their pregnant mothers' drug use, increased by 383 percent, according the White House Associate Director of Drug Control Policy Charmaine Yoest, who also spoke at the National Review Institute event.

"I want the pro-life community to acknowledge more what is going on with the foster care crisis in this country. I feel very strongly that in a lot of ways it is connected to our desire to eradicate abortion," said Lisa Ann Wheeler, the president of Carmel Communications. Wheeler has had five children, and has fostered 15.

For Sarah Zagorski, the connection between foster care and pro-life work is very clear.

"My mother consulted with an abortionist for my delivery," said Zagorski. "She was a Hispanic woman, very vulnerable woman, who already had seven kids in and out of foster care. They were already experiencing abuse, neglect, you name it."

After her mother chose life, Sarah said that "life got very complicated very quickly because I entered a family environment that was unstable."

"Foster care saved my life, just like the choice that my birth mother made saved my life," said Zagorski.

When Catholic couples adopt or foster a child, they are living out the Gospel call for a "radical welcoming of the stranger, the orphan," shared Elizabeth Kirk, the keynote speaker at "Fostering a Culture of Hope."

"Pope Francis stated … that the choice of adoption and foster care expresses a particular kind of fruitfulness in the marriage experience," continued Kirk. "Pope Francis urged even those with biological children to find other expressions of fruitfulness that in some way prolong the love that sustains them. Christian marriages, he says, are fruitful by their witness."

"Now is an important moment for the Catholic Church to step forward and really embrace fostering," explained Kathleen Domingo, who led a foster care initiative in the Archdiocese of Los Angeles after Catholic Charities was driven out of foster care and adoption in California due to a lack of conscience protection laws.

"Fostering is definitely a work of mercy," said Domingo, "and works of mercy are transformative."

"Having families in your parish involved in fostering with the rest of the parish coming around them to surround them and support them, can be that transformative element that can help our parishes to overcome polarization," she said.

There is a lot of untapped potential in our Catholic communities, according to Domingo, who together with Archbishop Jose Gomez launched a campaign to raise awareness of foster care needs in the Los Angeles archdiocese last October.

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They organized presentations at just 15 parishes in the archdiocese, and "the response was overwhelming," said Domingo.

"We had over 300 families in just 15 parishes come forward to register to get trained as foster families," she continued.

Even if someone is not called to foster or adopt a child, there are many things that Catholics can do to support these children.

"You can do anything from cooking a meal to providing transportation or even taking some of those children into your home. You can serve as a mentor. You can work and find ways to get your church involved," suggested Natalie Goodnow, a research fellow at the Wisconsin Institute for Law and Liberty.

One concrete way anyone can help is through respite care, recommends Goodnow. Respite care involves watching a foster family's kids for a couple days to a week, allowing the foster parents to have a break.

People can also volunteer as "court appointed special advocates," or CASA for short. Through CASA, a person is matched with a foster child's case, and advocates for the child throughout the duration of their time in the child welfare system. Goodnow pointed out that there is no legal experience required to participate.

Another organization Goodnow recommends is "Safe Families for Children", which supports struggling families at risk of being separated through foster care.

Tutoring and mentoring a teen in foster care can also make a transformative impact, said Goodnow, who continued:

"There is tremendous potential for the faith community to do even more. I don't think that we have fully tapped into what this community is capable of."