Why can't they risk it?

Found on r/tumbler

Brother sent this to me.. dont get it.

Is this a Seinfeld reference??

Esplain

Help, i completely missed the joke.

I'm slow

I like norm McDonald, but is this like a reference or something

I don't get it

I’m stumped. Thought maybe son was filling out a form. What does time and place of birth have to do with dating a girl?

“Trying for baby?” was the caption.