When you are becoming pregnant yourself you are not involving your sister. You are also not in a position of authority and having to make decisions based on ethical concerns.
Surrogacy is different because it has both elements.
Your sister is risking the health of someone else - who in your case has children.
A HCP should be considering the wellbeing of all vested interest groups.
Going back to considerations of safeguarding and rights.
Concerns in order of priority:
The baby being created
The existing children of the mother
The mother
The commissioning parents
A HCP and commissioning parents should be considering the following:
What happens if the baby has trauma or disabilities?
What happens if the mother dies or suffers life changing injuries?
What happens if the relationship between the mother and her blood relatives breakdown?
A mother deciding to have more of her own children will consider some of this, and maybe decide not to have more children.
If we are serious about protecting all parties in surrogacy, we should actually protect all parties.
In a surrogacy arrangement these normal considerations inevitably are much more complex and a HCP should have an additional responsibility, because they are enabling the pregnancy, to consider the potential impacts on the existing children because of this highly complex situation.
Given we are already seeing surrogacy being used as a means to allow individuals who would be rejected for adoption, to have a baby and we are already seeing various cases of manipulation of family members we should be doing this because the central focus should be on the children - not two adult women who come to an agreement between themselves. Cos life just doesn't work like that.
You risk some pretty fucked up court cases in the future if you don't.
And yet there's no obligations for extensive counselling and considerations of this. There's this airy fairy 'and we all lived happily ever after'.
I don't believe altruistic surrogacy should be allowed anymore than commercial. I think the fall out when it goes wrong is still huge and in some ways potentially more damaging.