ALOT of women DO NOT ovulate mid cycle, some ov RIGHT after af (sometimes during the last day or two of) and alot seem to ov very late on pretty a few days before ov, and your more likely to have these kind of ov times after you have already had a child/children. I know thats perhaps why there are OPK's and taking temps etc, but if most of us are BDing mid cycle and running all our obsservations and test mid cycle, that could be perhaps where we are all going wrong???? Just a thought/idea i guess