*Do you know what's 1+1?
No. Seriously!
I mean to ask it.*
Well it can't be generalized if you asked me.
Let me have the privilege of explaining how's, what's & why's...
Pay a bit of attention please...
Here, let me explain with examples...
Case I:
Consider a man & woman.
They marry each other to add into each other's lives.
They go for their honeymoon and have a baby (or some babies if multiple embryos succeed to develop).
Case II:
Consider unsafe sexual encounters.
Teenagers go for unwarranted sex with their counterparts and the girl gets pregnant. Here further cases of possibilities arise. Depending upon how either the girl or the boy and their parents react to the situation, there can be a single child or maybe multiple numbers of offspring here too!
So 1+1 = 2. Not always true!