As Teinyhr pointed out the last time this question came up, former senior writer CCP Abraxas clarified that capsuleers are not sterile by default.
In case the link doesn’t work for you, the post says this:
Here’s one: Capsuleers are not sterile by default, nor do they have any missing organs or interior plumbing. There is a slightly stronger tendency among them to have that stuff removed than there is among the general population, but it’s not anywhere near a majority of the entire capsuleer class.
You don’t see capsuleers (at least not the ones I’ve encountered) taking steps to rid themselves of any other base desires - greed, resentment, anger or hate - and I truly don’t see them wanting to rid themselves of the sexual one, either. Moreover, we don’t want the capsuleer option to be “You’ll be rich and powerful beyond your wildest dreams … but you can never have children.” It’s a decent hook for a story or two at most, but for any writing work beyond that, it’s far too restrictive.
So if they want, they can, but they don’t have to.
Edit: Tein also pointed out that the mother would have to carry the baby to term without changing clones/being podded, as a new clone would not have the growing baby’s DNA, etc.