For parents who use donors to conceive, an unexpected challenge of the process can be explaining the situation to the child. Here, experts offer tips and provide sample scripts for talking to kids about their donors.

Four years ago, my partner and I were sitting anxiously in a fertility doctor’s office. We wanted to have a child and because we’re both women, we needed a sperm donor. We got undeservedly lucky: Today our son is 3 years old and the in vitro fertilization process is far behind us. But, like other parents (gay, straight, or single) we’re finding that sometimes the hard part of donor conception comes after the wild journey of donor selection, countless doctor visits, and the long-awaited birth day.

Last year, the number of babies conceived through assisted reproduction technologies reached an estimated 5 million worldwide, making donor conception a mainstream medical issue. For those of us using donors to build our families, one of the most delicate issues of our parenthood is how to talk to our children about their donors. How do we weave the idea of this other person, often a stranger, into the story of their life? When’s the right time to discuss it? And what, exactly, do we say? We asked for some expert advice and put together a step-by-step guide on how to talk to your child about his donor.

Start Early

Most child psychologists agree that it’s never too early to tell the truth: The longer you wait, the harder the conversation will be. Some even recommend telling the story when your child is in the womb so you get used to telling it. My son started to pay attention to the story around the time he turned 3; your child may be ready earlier or later. Whenever the right time is for your family, be matter-of-fact about it; if it’s not a big deal to you, it won’t be to your child. Call the donor a “helper” or simply “the donor,” and refer to him in positive terms without romanticizing him. If you’re crafts-oriented, make a scrapbook with family photos, ultrasound pictures, and pictures from the birth. Focus on the makeup of your family, rather than the details of your child’s conception. You can say, “Mommy and Mama loved each other very much and wanted to have a baby. We needed help to make a baby because we needed a part that comes from a man. This man is called a helper or a donor. He gave us sperm, which is like a little seed. The doctor put the seed in Mommy’s belly. When Mommy’s belly grew very big, Mommy and Mama went to the hospital and you were born. Now our family is made up of Mommy, Mama, and you.”

Make the Distinction Between Donor and Parent

As your child grows, other children might ask him or her why he doesn’t have a “dad” or a “mom.” This is when the distinction between a parent and a donor is especially important. Madeline L. Feingold, Ph.D., a psychologist specializing in alternative family-building issues, suggests this script: “Even though we had all the ingredients to grow a family, we were missing some ingredients to make a baby. It takes three ingredients to make a baby: something called sperm, and sperm always comes from men, although not always from daddies; something called an egg, and eggs always come from women, although not always from mommies; and something called a uterus for the baby to grow in.” You can add: “Not all children have a daddy or a mommy. Some children have a helper or a donor.”

Talk, Talk, and Keep Talking

By the time your child learns about the birds and the bees, make sure she understands that intercourse is not the only way babies are made. If the donor isn’t in your life, this might be the time to share the rest of the information you have about her. You can add to the story: “Mom and Dad had the sperm and the uterus, but we didn’t have the egg to have a baby. We picked our egg donor because she wrote a very thoughtful letter about how much she wanted to help other families who could not have children by themselves. Once we had the egg, Mom and Dad went to the hospital and our doctor fertilized the egg with Dad’s sperm. That created an embryo, which the doctor put into Mom’s uterus. That embryo grew into a baby and you were born. Mom and I were so happy.”

Acknowledge and Respect Your Child’s Feelings

The donor conversation is hard for parents because we fear that our kids will be confused about their family. But “children are clear about who their parents are,” Dr. Feingold says. “When parents talk to their children about their desire to build a family and about the donor in the context of family building, they provide their children with the meaning that’s necessary to understand donor conception. Rather than feeling confused and frustrated, these children experience a sense of belonging. They appreciate the emotional bonds that tie them to their parents and create their family, understand their donor origins in relation to their identity, and always know they are loved and celebrated for exactly who they are.” But this doesn’t mean that your child won’t have complex emotions about the donor. Encourage your child to talk to you about his feelings. Keep the dialogue open and be prepared to answer questions when they come up, even if it’s at inconvenient times.

No matter how our families come together, we all want to raise happy, self-assured children. If you start the conversation early and keep reaffirming that all families are made by emotional rather than genetic ties, the story of the donor and the details surrounding your child’s conception will be a natural part of his family’s narrative.