Conception Date Is Not Always the Date of Intercourse
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Sperm can survive for several days, ovulation timing varies, and fertilization cannot ordinarily be assigned to one intercourse date by a calendar estimate.
Why dates differ
An estimated conception day represents a model center, not a timestamp. Show a window and preserve uncertainty.
Not paternity evidence
The result cannot establish paternity. Use appropriate clinical and legal processes for that question.
Estimate the window
Use the Conception Calculator to compare LMP and due-date methods.
Primary sources
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