When to have intercourse to get pregnant
Every other day, starting early.

Four well-placed encounters cover the window

Based on the Wilcox research on the fertile window, the book sets out the optimal strategy for a healthy couple trying to conceive:

1. Start 5 days before expected ovulation, when the mucus starts turning wet.
2. Have sex every other day throughout the fertile window.
3. Don't skip ovulation day, even if you had sex the day before.
4. Don't bother with several times on the same day: there is no benefit.
5. After ovulation day, the window is closed: you can rest.

Example: a 28-day cycle with ovulation on day 14

Example from Chapter 26 of Map to the Positive.

That's four strategically placed encounters that cover almost the entire fertile window. It works better than “every day for two weeks”, and it spares the couple.

Don't wait for the positive test

Relying on ovulation tests alone has a subtle problem: by the time the test goes positive, you're already late. The test detects the LH surge, which precedes ovulation by 24 to 36 hours. If you only have sex after the positive, you're doing it on ovulation day or just before. You catch the peak, yes, but you miss the four previous days, which add up to more than 80% of the window's chance of conception.

And once the test does turn positive, don't stop: you ovulate 24 to 36 hours later, so sex on the day of the positive and the day after still counts.

This is one chapter. The map has 42.

This strategy comes from Chapter 14 of Map to the Positive, in Station II, and is put into practice in Chapter 26, in Station III. Chapter 26 also covers how often to have sex outside the window, which lubricants harm sperm, whether positions matter, and how to keep sex alive when trying starts to feel like a task.