Customer (name blocked for privacy),
Sorry I didn't get back to you sooner- my connection died and I had to reboot everything.
If she has a 28 day cycle, then she ovulated around 05/12. Sperm can live for up to 72 hours once ejaculated, so any relations 72 hours before resulted in pregnancy, or 24 hours from the time of ovulation. If both yourself and the other person she had relations with had intercourse during this time, then the only way to know for sure would be to do paternity testing. If she is having CVS or an amnio done, testing can be done then otherwise it can be done after the birth.
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