Successful sex pre-selection using natural family planning.

The objective of the study was to test the hypothesis that gender can be preselected by timing coitus in relation to ovulation, the marker of ovulation being the Peak symptom according to the Billings Method. A blind prospective study of 99 couples wishing to preselect the sex of their child was conducted in Nigeria, using the Post-Peak approach of Billings Method for males and Pre-Peak for females. Research co-ordinators examined the 'post-conception' form within four months of conception. This form recorded the timing of coitus prior to conception, and from this, the sex of child was predicted. 94 of the couples had a child of pre-selected sex showing a method success of 94.9%. 78 of 81 predicting a male were successful (96.3%) and 16 of the 18 predicting a female (88.9%). There was one user-failure, a couple who wanted a girl, timed coitus as for a boy, which they had. The study indicates that where comprehensive instruction is provided, the sex of a child can be preselected with a high degree of confidence by timing coitus, using the Post-Peak approach of Billings Method for males and Pre-Peak for females.