Dogs and babies at Lakeside

I usually stop to admire dogs and babies when I'm on my walks. Today a man about 18" taller than me was rocking a cranky baby in a buggy. I stopped to peek and admire a little one who'd about outgrown the space.
Me: How old is he?
He: 10 weeks.
Me: Wow. He's big.
He: Weighed 8.5 lbs. at birth. But I was 9.
Me: I was 9.5.
He: Yeah, but I was a twin.