Regarding fetal sex preselection

Ovulona(TM) and bioZhena Corporation logo

A new friend, interested in the bioZhena technology and venture proposition, has written to me:

“One question that I’ve gotten is around the accuracy of sex selection. I know this is (or can be) a controversial subject. My wife and I (parents of 3 boys) tried using one of the methods in a book to have a girl on our second try. It didn’t work, obviously, and our son decided to come on his own. Could you please tell me more about that part of the test. I understand it in theory but probably it will need to go into clinicals to validate the claim – right?”

I responded fairly promptly, but without details such as the references and especially some graphics, and without expressing serious doubt about my friend’s book and the advice they had drawn from it. This was my response:

Of course, sex preselection is a controversial subject. Most important, though, is that you understand that this is not our initial product offering; it is merely a well justified expectation (speculation), which requires a study and investment, just like the early cervical cancer diagnosis as well as the birth control uses of the Ovulona technology.

What we have for immediate market introduction is the Ovulona as a tool for aiding conception, as previously passed by the FDA, and that did not include any fetal sexing claims.

[NFP = Natural Family Planning; FAM = Fertility Awareness Method]

We will introduce SFP, Scientific Family Planning. SFA, Scientific Fertility Awareness. All four ™-designated.

For your immediate understanding of this particular fetal sexing implications of the bioZhena technology, you presumably are aware of slide 4. Now I summarize for you where this comes from. Namely, I paraphrase from a detailed white paper, which is available for study upon request, if interested:

…a 1992 publication by John T. France et al., reporting data from 55 pregnancies (and births). The study was based on data whereby only one coitus per fertile period occurred, and three different markers were used to estimate the time of ovulation.

The stringency of the study design by France et al. went so far as to exclude 29% of pregnancies from the birth sex ratio evaluation in terms of timing of conception with respect to ovulation, because of more than one act of intercourse during the fertile period. Significantly, the birth sex ratio was 0.50 for this excluded group but far from 0.50 for the good study population.

The results of the France et al. study were as follows: Of the 34 male infants born, 65% were conceived 2 to 5 days before ovulation, and 71% of the born girls were conceived from intercourse timed between 1 day before to 1 day after the estimated time of ovulation. However, there was a great uncertainty about the actual ovulation day because in only 9% of the cases did the three ovulation markers agree with each other. In 68% of the cycles, agreement was within +/-1 day. The peak cervical mucus marker was one while the other two markers were the onset of the LH surge, and the basal body temperature rise.

Hoping that this mildly specialist language is not just mumbo jumbo to you, the key to this is your understanding that until the emergence of our device there has not been a definitive tool for this; that is, not only predicting but also detecting ovulation – and everything else follows from this simple fact.

The France et al. study was the best, better than some others, but even France et al. did not do everything right. For example, John France was not able to share those 9% of cases where the three methods, which they wisely used (to make up for the absence of a definitive tool), coincided in terms of the day of ovulation. Those 9% could have given us a better, almost definitive baseline. (5 definitive cases, if coincidence of three unreliable methods amounts to definitiveness. 5 = 9% of 55.)

K., this slip into details has been due to your scientific education and the personal level of your prior involvement with the subject, which presumably makes for an appreciation not necessarily to be found elsewhere, in other people.

Having quoted the question and answer verbatim, my next post will attempt to improve the answer (the answer to what may well be a burning question in numerous minds) with the illustrations and explanations. That is: Fetal sex preselection – illustrated . Check it out!


France et al. paper with data on fetal sex pre-selection, 3-day fertile window:

J.T. France, F.M. Graham, L. Gosling, P. Hair and B.S. Knox, “Characteristics of natural conception cycles occurring in a prospective study of sex preselection: fertility awareness symptoms, hormone levels, sperm survival, and pregnancy outcome”, International Journal of Fertility 37 (4), 224 – 255, 1992.

NIH paper:

A.J. Wilcox, C.R. Weinberg and D.D. Berg, “Timing of sexual intercourse in relation to ovulation. Effects on the probability of conception, survival of the pregnancy, and sex of the baby”, New England Journal of Medicine 333, 1517 – 1521, 1995.

Hodgen et al. paper on different survival times of X and Y sperm:

Q. Van Dyk, M. C. Mahony and G. D. Hodgen, “Differential binding of X- and Y-chromosome-bearing human spermatozoa to zona pellucida in vitro”, Andrologia, Volume 33, Issue 4, Page 199, July 2001


Tags: , , , , , , , , , , , , , , ,

2 Responses to “Regarding fetal sex preselection”

  1. Cervix uteri and seven or eight related things « bioZhena’s Weblog Says:

    […] illustration, go see another old bioZhena post, “Regarding fetal sex preselection”, at . Share this:StumbleUponDiggRedditLike this:LikeBe the first to like this […]

  2. What Women Know, And What They Want To Know About Their Fertility Status | bioZhena's Weblog Says:

    […] There is no device in the marketplace today that would tell you, in plain English, “today is your fertile day 1” – meaning that sex today is likely to lead to pregnancy. And from our clinical trial results you will know that the pregnancy conceived on this first of the fertile days is likely to be a male fetus, a boy. […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: