It depends whether your BF has a genetic history of depression. Not all depression is genetic, and not all of it is medically related, so it's hard to tell whether his children would even have any depression at all.

Agreed-

-yes it can be genetic, but isn't necessarily
- children raised in a home with a depressed parent are more likely to be depressed, even if they were adopted

So focus on raising your child in a healthy, happy environment and make sure your bf's depression is getting treated.