Lying is always risky, though. If the truth comes to light, you are screwed. Even if it doesn't, you have to remember and internalize your lie, and make sure anything you say in the future is consistent with it. That requires extra work and can be stressful. (And if you mess it up: again, you are screwed.)
I don't buy the "you don't want to work for a company that would ask you XYZ anyway" line. Sure, in some cases that may be true, but sometimes someone (that is, a random person on the interview loop, not a "professional interviewer" like a recruiter) will ask or say something they shouldn't, and that doesn't need to reflect poorly on the company (or even on the person; who hasn't said something dumb on occasion?).
If you think a question is inappropriate, politely decline to answer, using whatever verbal finesse you have available to yourself. It takes practice and confidence to do so, but it's the right thing to do.
The right answer to those questions is: Sorry but that’s quite a direct question, why do you ask? (And how is it relevant to this interview?)
Those are bad questions to ask as an employer, and you should probably move on to the next opportunity anyways. Still, faking to have children when you don’t, or the other way around, is worse.
I don't buy the "you don't want to work for a company that would ask you XYZ anyway" line. Sure, in some cases that may be true, but sometimes someone (that is, a random person on the interview loop, not a "professional interviewer" like a recruiter) will ask or say something they shouldn't, and that doesn't need to reflect poorly on the company (or even on the person; who hasn't said something dumb on occasion?).
If you think a question is inappropriate, politely decline to answer, using whatever verbal finesse you have available to yourself. It takes practice and confidence to do so, but it's the right thing to do.