He is the brother of Evelyn Forsyth.
On October 2, 2017, Joy-Anna shared a photo of her baby bump with a caption stating that the baby was "already about the size of a bell pepper and weighs around half a pound!!!".
According to the Duggar family blog, which is run by friends of the family, the baby was due in early March, 2018, and the couple has decided not to learn the gender of the baby in advance.
On February 13, 2018, the Forsyths posted a photo with the hashtag #9daystillduedate, indicating that the due date was February 22, 2018.
Gideon Martyn Forsyth was born at 3:39 pm on February 23, 2018. He weighed 10 pounds and 3 ounces. On February 26, 2018, his birth was announced on the Duggar family website, and his parents released the following joint statement on the TLC website:
"We are blessed beyond measure with the arrival of our son, Gideon Martyn Forsyth." say Joy and Austin. "Looking at our child for the first time was such an incredible moment! God is so good, and we are so thankful."
Although a video about preparations for his birth included mention of a birthing pool being prepared at home, pictures released after his birth seemed to suggest he may have been born in a hospital.
A few months after the birth, the couple shared more details, both in magazine interviews and on a TLC special. After 20 hours of laboring at home, Joy-Anna was rushed to the hospital for an emergency C-section due to fact that the baby was breech.