Applying logic to the argument in favor of relinquishing

I was told that because I was an unwed mother, and that my baby would not have her father in her life, I should give my baby up for adoption, so she could be raised by a married couple.

So, using this same logic, should a pregnant woman, if she becomes widowed during the pregnancy or shortly after the birth of her child also relinquish her baby for adoption?

How about a pregnant woman getting a divorce, or a new mom getting a divorce?  Should the child be torn from its remaining kin?  I mean, afterall, the child would never know a father.  That's the logic, right?

How about all the single women who adopt children?  I know two single women who have adopted children.  Oh, that's okay, right?  Why? 

The double standard is sickening.