When you match with a surrogate who will cocoon your baby for the next nine months, it’s the happiest moment imaginable. So how do you go about building this relationship and expressing your gratitude for this incredible gift?

Sarrah Strimel Bentley, 38, a breast cancer survivor and advocate, whose gestational surrogate, Whitney Washington, 32, is due with her baby boy at the end of December, does both by embracing her in every way possible.

“My husband, James, and I decided that, because of this magical chemistry that I have with Whitney, she became family,” said Bentley, who lives in Williamsburg.

Bentley found her surrogate, a nurse in Richmond, Va., via an agency. “Her kids came to our house in the Hamptons this summer. They call me auntie, they call my husband uncle and we plan to always be in each other’s life. We’ve gained an extended family.”

But that’s not always the way the intended parents feel about their surrogates, whether the person is a paid carrier or an altruistic surrogate (an unpaid friend or family member). Some want to keep the relationship transactional, while others prefer to limit communication or keep things very formal.

“The way you conduct this relationship is a very personal decision,” said Elizabeth Grill, Psy.D., a clinical psychologist at the Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine at Weill Medical College of Cornell University in New York City, who specializes in the emotional aspects of third-party reproduction.

This is why the initial matching process is so important.

“We’re very careful when we do independent evaluations of both parties and a joint session as well,” Grill said. “It’s a very involved process to get the right fit, but if it’s done right, well and ethically, the relationship should unfold pretty organically.”

An altruistic surrogacy arrangement is just as complex.

“When we assess an altruistic situation, we look at the family dynamics and look to see if there’s a sense of competitiveness, jealousy or an expectation that the person can’t say no,” Grill said. “We’re looking to make sure this experience adds to the relationship and doesn’t take away or cause problems down the road.”

With gestational surrogacy, where you are paying the surrogate to carry your baby, the same level of intense pre-screening is critical.

“If you want your carrier to be simply that, without any ongoing contact, holiday cards or get togethers in the future — and if your carrier is great with that — then you have a good match,” Grill said. “It has to be the right fit from the beginning and everyone has to ask the hard questions early on in the process.”

When in doubt, Grill said, it’s always best to ask your surrogate what you can do to show appreciation throughout the pregnancy. It’s important to get granular when asking, including how often you should be in touch to check in, whether you want regular photos or want to FaceTime during obstetrician appointments and more, all of which is as important as the legal documents that are signed.

“Keep in mind that being thankful — or being thanked constantly — can feel like pressure,” Grill said. “That’s why it’s important to communicate about anything that might come up. If your surrogate says she will check in once a month, that’s going to be something you need to talk about if that’s not satisfactory enough.”

Being thankful came easily to Marisa Merliss, in her 40s. She faced two very difficult health challenges in 2020 — she was diagnosed with cancer one month after delivering a stillbirth baby.

The silver lining: Her cousin Amanda Schulte, 39, a married substitute teacher and mom of three who lives in Kansas City, called Merliss the day she was diagnosed and announced she would be happy to be her surrogate. Three years to the day, Merliss’ baby daughter was born.

The cousins were a good match because they kept the lines of communication open and trusted each other implicitly.

“I knew that Amanda had the best interests of the baby in mind,” she said.

It helped that the two were constantly in touch.

“Amanda would send us sweet videos and we made road trips to see her every four to six weeks,” Merliss said. “My husband and I sent her flowers on Mother’s Day and care packages, even though she kept saying we didn’t have to.”

Bentley, who was diagnosed with breast cancer in 2020, now heads up a nonprofit, A Damn Good Life, that provides monetary grants for surrogacy. She herself had just one embryo — a single chance for a child — so finding the right person was critical.

“For maximum success we were looking for an angel, a needle in a haystack, who had to have a BMI under 22, she had to have carried her babies to full-term with no complications upon birth, and she had to be under 35,” Bentley said.

Bentley feels like she won the surrogate lottery.

“She’s bubbly and her laugh is infectious,” Bentley said. “She’s a relaxed happy human and she’s become another best friend.”

For all those reasons and more, thanking her is easy, Bentley said.

“The way I thank Whitney is by being part of her life,” she said. “She’ll ask me for relationship advice or what to wear to a Beyonce concert. I tell her every day that I love her and she tells me she loves me. The truth is that she is giving us the greatest gift — she is the miracle that is bringing our son here.”