5 years older to my sister and only sibling.
Eleven years.
I have a half brother who I haven’t seen since I was 18 months old. I want to say he’s about 16-20 years older than me, but I’d have to ask my mom for the exact number (he’s on my dad’s side, but she knew him a little and knows how old he is).
I have two older sisters: one is seven years older than me, the other ten years.
I was an accident apparently 
6 years, 5 months.
If we’re doing administrations: I was born under the Curtin adminstration; my brother was born 28 months later under the Attlee adminstration (in a different country, of course).
There’s eleven years between the two of us. The accident and the afterthought 
My sister is about 26.5 years older than me. My oldest brother is 30.5 years older (than me, not my sister!). My other brother is in between the two.
My younger brother, Larsornium The Inexplicable, was born 2 years, 9 months and 18 days after I was. That is, of course, in Terran time units.
Almost exactly 2 years either way. My birthday is at the end of March; my older brother’s and younger sister’s are both in April.
I am just under 15 months younger than my older brother. My mother had a miscarriage between the two of us. Then I have another brother that is 15 months younger than me. Our sister is 14 months younger than him. RCC for the overcrowding!
There are 4 of us born within 5-1/3 years.
4 years. My brother & sisters were the intentional ones.
Half-sister, and 23 years. She could be my daughter…
Me to Middlebro, 6 years and 2 months; Middlebro to Littlebro, 2 years and 6 months.
Our mother was sterile. Promise. The best ObGyns in Spain said so. Gives you a notion of what kind of ObGyn care could a woman expect in Spain in the mid-1960s (I’m a '68 vintage).
17 years.
My only sibling my sister is 21 years older than me, people ALWAYS assumed she was my mother and my mother my grandmother. Even up to high school this was assumed by everyone.:smack:
I am one day and one year older than my brother.
My brother is 17 years older than me; my sister two years older than him.
I was a 20th anniversary ‘surprise’.
Most are answering > 3 years, the demographics of the SDMB are interesting.