>>My partners are concerned that when you have this baby you are going to lose interest in the company and not be a good CEO As a practical matter this is a legitimate question. For example, "why are you taking this job when you plan to be busy for the next 6 months?" (or even longer).
As a practical matter, if someone in my company asked a candidate a question like that, premised on the candidate's ability to perform a job based on pregnancy status, I would fire the interviewer --- both because they were playing games with the most important function of the firm, and because they'd have exposed us to legal risk.