Unmarried and TTC

I am curious to hear from those who are TTC but aren't yet married.

What are your reasons for having kids first?

I understand for some it's a surprise and others who never plan on getting married. But for those who do plan on getting married, what are your reason(s) for having kids before getting married?

I don't mean this to sound judgmental or negative, it's not intended that way at all. I believe everyone should live their lives in the way that best suits them.

I'm just curious because to me, it seems like a natural choice to dedicate your life to your partner, then work on the ties that will bind you for life. Personally, I couldn't imagine trying for a child with someone who hadn't committed to me first.