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With a due date of 8/8/2016, the day of ovulation would have been 11/16/2015. As such, the only man that could be the father would be the man with whom you had sex on 11/14/2015. Sperm can sruvive in the female genital tract for up to five days, but it would be impossible for any sperm from the 10/31/2015 encounter to survive until the day of ovulation.
So, the due date would indicate that the father is the man with whom you had sex on 11/14/2015.
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