The blood renews each 3 years for women and 4 yeards for men. If woman's cycle was earlier the baby's gender will be female, If man's cycle was earlier the baby's gender will be male. In this case the Rhesus factor is very important. If mother has a negative Rhesus factor, the baby's gender will depends on the fact who has the stagnater blood.
This method was developed by Michael Freiman according to statistics of Svyatoslav Dobrotin, professor of the medical department of the Nizhegorodsky Medical State University. This statistics was drafted and checked during the Svyatoslav Dobrotin work in the I Maternity Home as chief medical officer in the Gorky city.
Freiman-Dobrotin's method