How do you have multiple families on at the same time????

That would be very cool, especially as waiting for the silly mother to drop her bundle of baby takes F O R E V E R!

Please give detailed instructions...

(Just FYI, I'm on my fourth family because none of them would have babies, but now finally, i have two 'definitely' want kids and they are popping them out like rabbits but the waiting is driving me insane! So I was seriously thinking about time travel!)