Another millennial adding on:

5. Bringing a sentient life into a world of suffering and climate change that will only worsen seems malicious to that life, at this point.
6. My partner really doesn't want to go through the body changes that come with pregnancy.

Additional emphasis on #3, even if it didn't compromise safety, a healthy pregnancy is expensive! Healthcare from any complications is financially devastating.

Small aside that adoption is not off the table for us, but we're not financially comfortable to get a dog yet, which we've been saving for for a few years. One of us would need to get a huge raise to be able to afford the costs of adoption and raising of a human child.