Be warned I'm about to ask what might be a silly question, but I'm going ahead and asking it anyway!

My sister has had two beautiful boys (3 and 1), both via c-section, both scheduled, because her OB told her that she would not be able to give birth vaginally as the boys' "heads were too big". Both boys were in the vacinity of 9lbs (can't remember exact weights sorry). My sister and I are both curvy and short (she's 5' I'm 5'2").

I'm trying for my first and my sister continually tells me that I should prepare myself for a c-section as "big heads run in the family". I usually just say "oh, well, we'll see", but it's getting to me as I am a) hoping for a natural (possibly home) birth and b) I'm TERRIFIED of having a c-section as I have had weird reactions to painkillers and anesthetic in the past. Obviously, I know that a healthy baby (and mother!) is the most important outcome and I would have a c-section if I had to for health reasons but I'd like to at least try to birth vaginally if possible.

Is it true that I am likely to have a c-section just because my sister has? What of this "big heads" business?

Thanks in advance for your advice to a newbie