"It's crazy to see that people were referring to my family as an inspiration," Melanie told The Huffington Post.
"We are still in complete shock."
The pictures show the women together when each one is pregnant, in a series of snaps that show how they supported each other as their bodies - and their family - changed. Other photos show them with one child when the other is expecting, and then with their family of four.
Each wanted to be mothers, so they said said the decision to create their family of four was an easy one.
The Roys hope by sharing the experience they would inspire other same sex couples to start a family.
"The woman's body is incredible," Melanie said.
"The way it creates and grows another human being is amazing. We hope that our picture is that sign that some women may need to encourage them to carry a child."
The women did not elaborate on how each of them conceived.
In January 2014 Vanessa was pregnant with Jax and just 12 months later Melanie was carrying Ero. They were photographed exactly a year apart and then uploaded the photos to Instagram earlier this year.
When the photos became popular - reaching over 150,000 likes on the Facebook page of a Brazilian advocacy group alone - Melanie took to her own page to say thank you.
"I am so thankful for the life I have been given," she wrote.
"For my two gorgeous healthy kids Jax and Ero. For my kickass wife who is literally my best friend, my therapist, my lover, and my partner in life all wrapped in one. My parents for all the things they sacrificed to give me the childhood I had and the solid foundation built with family, love, and tradition.
"My wife's parents for accepting me as one of their own and always being there for us.
"This positive move to Charlotte wouldn't have been possible if it wasn't for them. I've also been blessed with great friends along the way. Tonight while laying next to my two munchkins my heart was filled with love thinking of how awesome my life is."
- Daily Mail
