I've gotten myself in a tricky situation.
Before finishing my PhD I applied to several positions, both faculty and postdoc. I received offers for a postdoc position at one of the top universities in my field and an tenure-track faculty position at a good university with a very good salary. Since I really wanted to do a postdoc, I asked to defer the faculty position for one year and it was accepted. They made it clear however that they could only "reserve" the position for 1 year, any further delay would cancel the appointment.
Few months into my postdoc, we found out my wife is expecting and the baby (our first) will arrive the month I'm suppose to move to the new uni. This means that during the final month we would need to search for house in another country, have the baby, arrange for the move, prepare for the new position, move the newborn baby to a new country, find new doctors, etc. I cannot move alone (and don't want to) since it will be too hard on my wife (we have no family in either countries).
My current lab offered to extend the postdoc for another year. However, I would need to back down from my agreement with the other uni. Will this kill my opportunities for a faculty position the years to come? Will it put me in the spot of explaining at every future application that I'm not a badly educated person?
P.S.: just for the record, I was/am really looking forward for the faculty position and I'm not happy that I'll have to do the whole interviewing procedure again...