Be careful about reading health books. You may die of a misprint !

I remembered this quote by Mark Twain when visiting the The American Pregnancy Association website. They provide an Ovulation Calendar to help women conceive by tracking their fertile days. However, the fertile dates marked on their Ovulation Calendar are completely wrong ! The fertile days are the days of ovulation, and a 3 day window before this. Once the woman ovulates she becomes infertile ( because the cervical mucus becomes hostile). Thus, if a woman has her period on 1 Jan 2006; and the length of the cycle is 28 days , the fertile days should be 11 Jan - 14 Jan . Their calendar marks the fertile range from 11 Jan - 21 Jan ! By providing such a large ( and inaccurate) range, they have defeated the entire purpose of the calendar ( in
my opinion).
Our fertility calculator is much more accurate !