Robert Todd Lincoln --The vitals

[AussieMick]

I think that Lincoln would have had some inkling about the gestation period for human beings (Robert's birth could ... could ... have just about been due to you-know-what late in October ... but Mary wouldnt have been sure she was pregnant until about mid December at the earliest ... I hope, being a mere male, I've got this all correct). The question of a rushed marriage seems nonsensical if its based upon Robert's birth.
Of course they could have been 'having relations' for several months.
And I guess it could be that Mary was the temptress ... but this implies a certain naivety on Lincoln's part.
It takes 2 to tango.

I think Lincoln was a man of the world and knew what was what ... to suggest that 'Mary tricked Lincoln into marrying her by seducing him and then the very next day told him she was with child' is ... well, not credible.