Shettles Method Baby Gender Planner (Ovulation & Timing)
Plan your conception timing with the Shettles Method calculator. Estimates Peak Fertility and suggests dates for "Boy" or "Girl" attempts based on cycle length and ovulation timing.
Shettles Recommendation
About
The Shettles Method, developed by Dr. Landrum Shettles in the 1960s, posits that the timing of intercourse relative to ovulation can influence the probability of conceiving a specific gender. The theory rests on the distinct characteristics of X-chromosome (female) and Y-chromosome (male) sperm: Y-sperm are faster but more fragile, while X-sperm are slower but more resilient.
This planner calculates your estimated fertile window based on your menstrual cycle history. It delineates specific days for "Boy" attempts (aiming for close proximity to ovulation to favor fast Y-sperm) and "Girl" attempts (aiming for 2-4 days prior to ovulation to favor resilient X-sperm). Disclaimer: This tool is for entertainment and planning purposes only. Scientific consensus on gender selection via timing is mixed, and no natural method guarantees results.
Formulas
The calculator estimates the Ovulation Date based on the Luteal Phase (fixed at typically 14 days for most calculations, though variable in reality). The standard calculation is:
Based on this date, the gender-specific windows are defined as:
Fertility peaks at Dov and declines rapidly within 24 hours post-ovulation.
Reference Data
| Factor | Boy Attempt (Androsperm) | Girl Attempt (Gynosperm) |
|---|---|---|
| Timing | 12 hours before to Ovulation Day | 2 to 4 days before Ovulation |
| Sperm Type | Y-Chromosome | X-Chromosome |
| Characteristics | Smaller, Faster, Fragile | Larger, Slower, Resilient |
| pH Environment | Alkaline (High pH) | Acidic (Low pH) |
| Abstinence | Refrain for 4-5 days prior to attempt (High Count) | Frequent intercourse prior to cutoff (Low Count) |
| Shettles Success Rate | Claimed 75-90% (Debated) | Claimed 70-75% (Debated) |