Is it possible to have multiple colonizable planets in your starting system?

I ended up starting new games with a custom race continuously for about 15 minutes and only ever ended up with one colonizable planet (already colonized of course!) that was sized somewhere between 16-18. Is it possible for a random starting solar system to be generated with multiple colonizable planets? And if not, are there any ways to increase the number of colonizable planets in the starting system during gameplay?

Note that I'm not really interested in habitats as I'm more interested in having access to multiple starports for the purposes of this question, and I'm aware of Mars in Sol which is why I'm asking about random starting systems.

Yes, this is possible- it happened to my friend. She often plays with the habitable planets setting turned up though, so that might have been a factor.

You mentioned not counting habitats but not why you needed multiple spaceports. If it's just an issue of fleet capacity, habitats do give a bonus to fleet capacity, along with the extra from their pops.

Though if you really want to add more habitable planets to your starting system, one of the results of the Horizon Signal event can do this. Follow the instructions and the end result will turn every planet in your capital system except gas giants (so molten, toxic, frozen, or barren worlds) into an empty, colonizable planet.

I won't go into the details but the event has a random chance to trigger when a Science ship enters a black hole system. Apparently you can force it by repeatedly having a ship enter and leave that system.