I explained that, in a way, he did. That Mommy has eggs and Daddy has sperm and when they come together they make a zygote which grows into a fetus, which becomes a baby. He was satisfied with that answer. That was when he was four years old.
Then when he was seven, paging through a book about the human body, he asked me. "Mommy? How did Daddy get the sperm inside you?"
My moment had come. To tell him the truth.
So I did.
I was so proud of his reasoning mind.
I told him, "Well, sometimes if two women want to have a baby together, then a man can share his sperm with them to make a baby. And if two men want to have a baby together, then a women can share her egg and her body to help them make a baby."
Fast forward to a bit of time later. Coen's four year old sister Lucy was telling us that she was going to marry our neighbor, Zef. But then one day, in the parking lot at school, she saw her friend Josie.
"I'm going to marry Josie!" Lucy proclaimed.
"I thought you were going to marry Zef." Coen said.
"Well, now I'm going to marry Josie." Lucy said.
"That's okay!" Coen said brightly. "If you marry Josie, Zef can be your donor!"
I love my kids so much.