Could the timing of fertilization, in relation to the timing of intercourse, be a cause of unexplained health problems at birth?(SCS time = AOs − 365 hours ± 12–24 hours)
Three fundamental questions
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Do you think this hypothesis is worth investigating?
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The SCS timing hypothesis requires independent scientific validation. This content is not medical advice or a method of contraception. Discuss health decisions with a qualified healthcare professional.
An invitation to research
29 years of observations
Following 29 years of observations and work, SCS opens this question to women worldwide, scientists and health institutions.
Invitation to independent research
Three Questions Open to Independent Research
SCS does not ask the scientific community to accept the following observations and hypotheses as true. Instead, it asks independent researchers to measure, test and, where appropriate, falsify each one.
These three questions can be investigated independently. Validation of one does not automatically validate the others.
Don't believe us. Measure.
01
Open to independent research
Does the timing of fertilization matter?
Could the timing of fertilization be an independent variable worth investigating in relation to pregnancy and neonatal outcomes? For this purpose, SCS proposes a predefined, individually calculated timing variable.
SCS time = AOs − 365 hours ± 12–24 hours
AOs is the individual average, in hours, of intervals between consecutive menstrual start date-times.
26.3 days equals 631.2 hours.
Example calculation
Three cycles: 627, 635 and 605 hours. Total: 1,867 hours; divided by 3, AOs = 622.3 hours. The center is 257.3 hours after the last menstrual start. The interval is widened according to the distance of AOs from 631.2 hours.
Research question
After adjustment for established maternal, fetal, genetic, environmental and obstetric factors, is this predefined timing variable associated with pregnancy and neonatal outcomes?
i
This formula is part of the SCS hypothesis; it is not an established medical fact, a contraceptive method or clinical advice. It must be independently validated or falsified.
02
Open to independent research
What is the actual interval from fertilization to birth?
The SCS observation from 29 years is that the interval from fertilization to birth is approximately 260 days. A more specific hypothesis that Osman Yıldız asks researchers to test independently is that adverse-outcome risk may increase as this interval extends and that an interval exceeding 266 days may not be compatible with live birth.
i
This is not established medical knowledge. It is an SCS hypothesis that Osman Yıldız asks to be validated or falsified with independent data.
IVF/ICSI research questions
In IVF/ICSI pregnancies, where fertilization timing can be constrained more precisely, what is the actual distribution from fertilization to birth?
Is the 260-day observation supported by the data?
Is there a measurable association between intervals beyond 260 days and adverse outcomes?
Are there live-birth cases with a fertilization-to-birth interval exceeding 266 days?
Do not accept 260 or 266 days. Measure them with your existing data.
Question 2 is independent of Question 1. Validation of the 260-day observation would not automatically validate the SCS timing formula.
03
Open to independent research
Does SCS timing correspond to a measurable physiological transition?
The female reproductive system is not in the same physiological state throughout the menstrual cycle. Hormonal patterns, basal body temperature and cervical-mucus properties can change around ovulation. The third SCS question is whether the mathematically predefined SCS interval systematically coincides with measurable fertility markers.
Measurable markers
Independent researchers could compare SCS timing with LH change or surge, ovulation timing, progesterone, estradiol, basal body temperature, cervical-mucus properties and markers of suitability for sperm penetration.
If considered appropriate by the researcher, physiological breast or nipple changes, subjective sexual desire and timing of sexual behaviour could also be recorded prospectively.
The SCS mechanism hypothesis
The mechanism hypothesis arising from Osman Yıldız’s observations is that cycle-related changes in the suitability of the cervical and reproductive environment for sperm passage, survival and selection might affect not only the probability of fertilization but also the biological consequences of its timing. This mechanism is unproven.
During the SCS interval, does the cervical environment differ measurably from other times in sperm passage, survival or selection? If so, is that difference associated only with the probability of pregnancy, or also with pregnancy and neonatal outcomes?
Behavioural and sensory observations
SCS observations report changes in body odour, sexual desire or other sensory and physiological features around the timing in some women. These cannot be treated as evidence without controlled scientific measurement, but they could be measured as additional variables in behavioural-endocrinology or reproductive-physiology studies.
Independent Research
SCS provides research infrastructure
Subject to independent ethics approval and informed consent, SCS is prepared to provide researchers free of charge with the software infrastructure required to investigate these three questions.
The researcher can define the protocol and inclusion/exclusion criteria.
The researcher can select participants and establish an independent cohort.
The researcher can follow participants through a dedicated panel and determine the physiological and clinical variables to be recorded.
The researcher controls statistical methods, analysis and publication, and may publish whether the result supports or falsifies SCS.
AOs is the individual average, in hours, of intervals between consecutive menstrual start date-times.
SCS time = AOs − 365 hours ± 12–24 hours
The center of the calculation is AOs − 365 hours.26.3 days equals 631.2 hours.
When AOs is close to 631.2 hours, the interval is approximately ±12 hours; as the individual average approaches the 24- or 28-day boundaries, it widens up to ±24 hours. The exact intermediate calculation is not disclosed here.
Example calculation
Three cycles: 627, 635 and 605 hours. Total: 1,867 hours; divided by 3, AOs = 622.3 hours. The center is 257.3 hours after the last menstrual start. The interval is widened according to the distance of AOs from 631.2 hours.
Menstrual start times→Individual hourly average (AOs)→AOs − 365→SCS interval→Pregnancy and birth outcome
i
This formula is part of the SCS hypothesis; it is not an established medical fact, a contraceptive method or clinical advice. It must be independently validated or falsified.
An invitation to research
Let us evaluate the evidence together.
Supporting, contradictory and inconclusive findings should be treated with equal openness. This page does not present a completed independent validation study.
Transparency of methods and data
A history of 29 years of observations is not, by itself, scientific evidence. Participant counts, recording methods, evaluation criteria and limitations need to be documented.
Independent research collaboration
Researchers are invited to share methodological critiques, comparative study proposals and relevant publications. Research data collection requires a separate protocol, ethical review and appropriate permissions.
An independent source of general health information
World Medical and Scientific Community: Join the Discussion
SCS is not asking you to believe this hypothesis. Examine the three questions through your expertise, critique them and discuss them using independent evidence.
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