Quelquefois, comme Ève naquit d’une côte d’Adam, une femme naissait pendant mon sommeil d’une fausse position de ma cuisse.

Sometimes, like Eve born from a rib of Adam, a woman rises during my sleep from a false place on my thigh.

I find this passage a little risque as the French say.  Here is Moncrieff’s translation,

Sometimes, too, just as Eve was created from a rib of Adam, so a woman would come into existence while I was sleeping, conceived from some strain in the position of my limbs.

I have no idea what he means by this . . . and it seems a little tamed down.