Does going overdue (or being early?) run in families?

[MsSampson]

I feel like I've read, or been told, that your likelihood to go overdue is correlated with your own mother's or sister's experience. Is this actually true, or just nonsense that I have nonetheless believed and repeated?
(currently 39+6 and extremely fed up and clutching at straws. Both DM and DSis went 40+10ish with first DC, then 4 or 5 days with DC2, so im banking on DC 2 turning up around Friday, which would fit in nicely with plans )

I suppose it must have a lot to do with the reasons for the prematurity - my sister and I were born at 35 and 34 weeks so I was expecting to pop early but I'll be 37 weeks tomorrow and no sign of anything imminent happening here so I suppose whatever caused my mum to give birth early hasn't passed on to me!