Of course I would. There's nothing 'weird' or 'creepy' about this.
You could meet someone, like them, sex them up, and then their single dad meets your single mum, they get on (and get married), all of a sudden you and the other girl(or boy, whatever) are 'sick' and 'disturbing'? Of course not. Ludicrous. This is the same situation, just reversed.
If you've grown up together it's another issue, but that's not what we're discussing.
(side-note: I wouldn't bother unless the step-sibling was something above 'normal' though, because potential awkwardness later wouldn't be worth it. I cba with that.)
You could meet someone, like them, sex them up, and then their single dad meets your single mum, they get on (and get married), all of a sudden you and the other girl(or boy, whatever) are 'sick' and 'disturbing'? Of course not. Ludicrous. This is the same situation, just reversed.
If you've grown up together it's another issue, but that's not what we're discussing.
(side-note: I wouldn't bother unless the step-sibling was something above 'normal' though, because potential awkwardness later wouldn't be worth it. I cba with that.)