Father 39, Mother 38. Officially I was the 2nd of two children (but I am skeptical).
My Live birth certificate said there was two deliveries prior to my birth. My sister says one prior to her birth. I know Mom had a miscarriage, but that doesn’t count as delivery, does it?
Only child. Mom was 35, dad was 54. Some retirement gift. 
I was beginning to wonder if I was the only one born to young parents. My Mom was 19, my father was 18. I am an only child (well, I have a half-sister on my father’s side, but… long story.)
31 and 41. First child for both 11 months after the wedding.
#3 arrived when they were 39 and 49. Yowza.
Dad 45, Mom 38. Second child. I’m also the youngest first cousin on both sides of my family - I was born laaaaate.
It could’ve been a stillbirth, or death shortly after birth. My mother had two sets of twins, but one set was born very prematurely and didn’t make it. My mother didn’t count them among her children if someone asked how many kids she had, but they were born and died and mourned.
StG
23 years (approximately - Mom’s birthday’s 3 weeks before mine, Dad’s 3 weeks after - yes, I am EXACTLY equidistant between them). First born. Didn’t come around until they’d been married for about 4 years.
My Mom was 18, and my Dad was 22.
My Wife’s Mom was 15, and Dad 17.
Mom was less than a month past her 18th birthday, Dad just over a month past his 23rd. I was the first of six born, five surviving (the one lived for just a day).
Mom 20, Dad 24. First in family, first grandchild on both sides of family.
Mother 24, Father four days short of 27. I’m their first child.
When my own first was born, her mother and I were both 25.
Dad was 32 when I was born. Mom was 25. I am his second child and her first. Both of them have passed on–Dad in 1980 and Mom in 2006.
Mom was 27 and Dad was 25. I was the first of five for both of them.
My father was 51, my mother 37. I was their third child (my father’s fourth). My closest sibling was almost 15 when I was born.
Father 28
Mother 22
Only child
My dad was one score and seven and my mom one score and six when I became the middle of three.
My mom was 41 and my dad 43. The youngest of 3 (my brother and sister are 17 and 19 years older than me), I was a 20th anniversary ‘surprise’ 
When I was born, my mother was 32 and my father was almost 32.
Mother was 18. The man who claims to be but yet can’t be my father who is named on my birth certificate was 19. I’m an only child.
Hubby - mom 28, dad 35. He is the oldest of three.
Sixth kid, dad 36 years older, mom 33 years older, ten years younger than oldest sibling.