Is it too weird if my stepdaughter becomes the surrogate mom for me and her dad?

My husband and I want to have a child, but I have bipolar disorder, and he doesn't want me to carry the child because of the complications that might happen due to the medications I'm taking.

Paying for a surrogate is too much for us. We are wondering if his daughter from his ex-wife will be willing to carry the baby, but it will still be our genes.

I worry that it would be too weird. We haven't asked my stepdaughter if she's willing to.

Can I get some perspective?

Thank you.
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I didn't mention this but the money would be a really big help to my stepdaughter too. She has a son and she's struggling to keep a job.
Is it too weird if my stepdaughter becomes the surrogate mom for me and her dad?
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