[bvs science freak]

Animal biotechnology- Assisted Reproductive Technology(ART).

Timing methods
Timing methods aim to affect the sex ratio of the resultant children by having sexual intercourse at specific times as related to ovulation, but have shown no influence on the sex of the baby.[14]
The Shettles method, first formally theorized in the 1960s by Landrum B. Shettles, proposes that sperm containing the X (female) chromosome are more resilient than sperm containing the Y (male) chromosome. The method advocates intercourse two to four days prior to ovulation. By the time ovulation occurs, the cervix should contain a higher concentration of female sperm still capable of fertilization (with most of the male sperm already dead). Intercourse close to ovulation, on the other hand, should increase the chances of conceiving a boy since the concentration of Y sperm is be higher at the height of the menstrual cycle.[15]
The Whelan method is an "intercourse timing" method that advocates the opposite of the Shettles method. The Whelan method suggests intercourse four to six days prior to ovulation to increase likelihood of fertilization by male sperm.
Reference link
http://en.wikipedia.org/wiki/Sex_selecti...son_method

Is that really true?
There is any difference between Male sperm (Y chromosome containing sperm) and Female sperm ( X chromosome containing Sperm) in Speed of migration,Mass,Longevity based on Acidic or Alkaline environment?