Maybe it's just me but I prefer this option. You can already change who can/can't get pregnant and such, which allows a lot of options with pregnancy (though I know not all). There is no way to have a genetic baby without pregnancy at all so I'm happy to have this. The only thing I'd change is having to wait a few days, like you go in, then a few days later you get the baby. Though I can see that being a potential issue with household sizes and such so I get it.
It could be nice to have a second option as 'get pregnant with science baby', then choose sim to get pregnant and optional other sim.