I developed this long time ago about 10 years back and I continue to improve it when I came across something interesting. :P
One of my favorite in advancing my skill in Excel formula. LOL.
Anyway, this is actually used to pin-point when is my ovulation and to increase the conceive chances.
Then later on, when I knew about "Shettles Method" - I added when should start to have sex and when not-to to have a baby boy or girl.
Then, it went on and on for estimation baby date dues (40 weeks from the last period) because I want to be the first one to know instead hearing from the doctor.
Then later I wish to know, when the baby really born on the estimate date dues, what is the zodiac like and so on, so I develop this to entertain my curiosity. LOL :)
Anyway, this developed for my own use only.
P/S: Sorry, this is not for distribution. Use it at your own risk.
P/S: I taught a friend of mine about 4 years ago on how to calculate the safe period and I told her it is very important not to miss any day or else you will end up pregnant. She told me she will be very careful and you know what. She let Saturday & Sunday on leaves and she end-up pregnant. Well, she is blessed with 2 sons and one is on the way.