They pretty much all are pregnant right now except Fiona and the Doctor and concerning the Doctor (I've forgotten her name, sorry!) we really haven't been able to date her just yet, but by the end of 0.21 the process to date her as begun, that's if as playing as the MC you decided you wanted to impregnate them of course. I think you can have as many or as few girls in your harem as you want and who want but you will have to date them and get to know them on a personal level and you can decide if you want to impregnate them once you have got to know them and form a relationship with them. Very much many of the girls have their own back stories that are very much worth reading, especially Lucy, Fiona and Becca story lines. There is also little Alice to, which is a very interesting story which also concerns the MC, but its very much up to you in this game, who you want to be with and who you want to get pregnant or not.