Lots of studies

[rainbowflower]

I found this the other day: http://www.niehs.nih.gov/research/atniehs/labs/epi/studies/eps/publications.cfm
and it contains a list to lots of pregnancy and some gender-related studies that are quite interesting

[nuthinbutpink]

This one is interesting- The timing of the “fertile window” in the menstrual cycle: day specific estimates from a prospective study

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC27529/?tool=pubmed

What is already known on this topic

According to clinical guidelines, the average woman is potentially fertile between days 10 and 17 of her menstrual cycle
This assumes that ovulation occurs exactly 14 days before the onset of the next menses, and that the fertile window extends before and after ovulation; however, these assumptions are based on outdated information

What this study adds

The timing of the fertile window is highly variable, even among women who regard their menstrual cycles as regular
More than 70% of women are in their fertile window before day 10 or after day 17 of their menstrual cycle

There are few days of the menstrual cycle during which some women are not potentially fertile .

[nuthinbutpink]

The sex of the baby may be related to the length of the follicular phase in the conception cycle.

Abstract

In a prospective study of normal couples discontinuing contraception to begin a pregnancy, the days of ovulation were estimated by hormonal assay of daily urine specimens. No hormonal interventions were used. Length of the follicular phase (from onset of menses to ovulation) was found to be related to the sex of the baby among 133 pregnancies that survived to delivery. Conception cycles with short follicular phases (early ovulation) tended to produce boys, while those with long follicular phases tended to produce girls. This relationship is consistent with other data and could explain sex-related differences in the length of gestation and the observed excess of same-sex pairs among dizygotic twins.

[nuthinbutpink]

Timing of sexual intercourse in relation to ovulation. Effects on the probability of conception, survival of the pregnancy, and sex of the baby.


Abstract

BACKGROUND: The timing of sexual intercourse in relation to ovulation strongly influences the chance of conception, although the actual number of fertile days in a woman's menstrual cycle is uncertain. The timing of intercourse may also be associated with the sex of the baby.

METHODS: We recruited 221 healthy women who were planning to become pregnant. At the same time the women stopped using birth-control methods, they began collecting daily urine specimens and keeping daily records of whether they had sexual intercourse. We measured estrogen and progesterone metabolites in urine to estimate the day of ovulation.

RESULTS: In a total of 625 menstrual cycles for which the dates of ovulation could be estimated, 192 pregnancies were initiated, as indicated by increases in the urinary concentration of human chorionic gonadotropin around the expected time of implantation. Two thirds (n = 129) ended in live births. Conception occurred only when intercourse took place during a six-day period that ended on the estimated day of ovulation. The probability of conception ranged from 0.10 when intercourse occurred five days before ovulation to 0.33 when it occurred on the day of ovulation itself. There was no evident relation between the age of sperm and the viability of the conceptus, although only 6 percent of the pregnancies could be firmly attributed to sperm that were three or more days old. Cycles producing male and female babies had similar patterns of intercourse in relation to ovulation.

CONCLUSIONS: Among healthy women trying to conceive, nearly all pregnancies can be attributed to intercourse during a six-day period ending on the day of ovulation. For practical purposes, the timing of sexual intercourse in relation to ovulation has no influence on the sex of the baby

[rainbowflower]

yes it's that last study you mentioned that led me to the original list I posted - fascinating that less than 10% of pregnancies come with a 3+ day cut off, and that the genders are still roughly 50-50 even on OV day

[atomic sagebrush]

You guys ROCK!!!