This is a question my husband had when I wanted to hire a doula for Bryson’s birth. I reassured him they didn’t. When we met with Alison and talked with her about her role, he felt much better about it. Then after the birth he wondered why we didn’t have one for each birth?
He LOVED having a doula! He was not replaced at all, rather he felt as if he had a huge weight lifted off his shoulders, he could relax and enjoy the birth and let someone else (Alison) worry about the details.
I have found that sometimes dads are worried about this. But if you ask any dad who has had a doula at his child’s birth, they are the biggest supporters and say it is great!
Here is a great chart explaining why doulas do NOT replace dads!