Depends on the specific circumstances, but i feel like it can be just as much of an issue, if you want children and don't even care if they are biologically related to you.
Depending on how much the other parent of ones stepchildren is involved in their lives and their age, taking on a parenting role might not be wanted or even allowed. So you might have children living in your house, but won't ever have a complete parental relationship with them. You will always have that additional relationship that needs to be build around, whether that be vacations or where you live.