Does marriage really matter to have a baby? I think as long as you can support the child financially and emotionally it's all good.

Two parents in a stable relationship are better than one.

But I know a number of single parents (all women) who have done a really good job under difficult circumstances bringing up children.

There are no rules, (but I do think that two parents are better than one, for all sorts of reasons).

No. Marriage is a man made ritual that is not required to have a baby. Two partners could be great parents just as a married couple could.

In the grand scheme of things, marriage often just a piece of paper.  If parents love and care for each other and their children it really doesn't matter. What matters is the commitment to do your best for your child. I have known couples wh never got married and have lasted longer than many married couples. 

Parenthood is about caring and nurturing and sharing your humanity with your children, but it is also---unavoidably---a model of interaction that you wind up sharing with those children which determines what they think is acceptable in the male-female relationships they will enter into as adults.

So, without their knowledge---and apparently without yours either---you are giving them opinions about the importance or non-importance of divorce, commitment, pair bonding, etc..

Personally, I think that being a good mother also requires being a good wife; just as I think that being a good father requires being a good husband.

I do think that single parents often do heroic jobs in raising their children, but I would not want to suggest that become the norm.

Marriage doesn't matter.  As long as the parents are emotionally and financially ready to raise a child, I don't see why you wouldn't be able to.