Well I believe we must not define haram or halal depending on what we think is good or bad. Already such haram and halal fatwas has damaged us alot. In surrogation in vitro fertilisation is performed and then fused cells are planted in female web and I guess there is no sexual activity in this process.
Secondly if another woman can breastfeed then why can’t she just deliver baby. Breastfeeding from another woman is allowed both in our laws and our religion.
In my opinion its just an individual concern. Someone wishes to be parent and other one consents to be a carrier. And it’s implications on society are not so clear yet.
Hormonal Implications result in the induced reproductive system. Think about it?