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MicroSort FAQ

If I conceive twins with MicroSort, what are my odds of having boys and/or girls?

Your first question about MicroSort and twins is probably, "how do I avoid having them?" not, "what are their genders probably going to be?" But in case you do conceive twins using MicroSort, here's the answer.

This question is particularly interesting to me, since I conceived boy/girl twins with a 92% sort for a girl, and I've always wondered what the odds of this happening were. Plus I've seen a few other MicroSort twin moms go a little nutty trying to figure out the odds that they were having at least one girl, or twin boys! Here are the numbers.

Gender Odds of MicroSort Twins

This table shows gender odds for twins after MicroSort XSort for a girl, given the sort percentage shown in the first column.

For odds when trying for a boy, just reverse "girl" and "boy" in the titles below.

Note that even at a very low sort percentage, with twins the odds are very good that at least one twin is the desired gender. With only a 70% sort there is a 91% chance that at least one twin is the desired gender -- though there is a 9% chance that both are opposites.

In my case, we see that for a 92% sort, the odds of having boy/girl twins are 14.7%.

Sort % Odds of
At Least 1 Girl
Odds of
Twin Girls
Odds of
Boy/Girl Twins
Odds of
Twin Boys
70% 91.0% 49.0% 42.0% 9.0%
71% 91.6% 50.4% 41.2% 8.4%
72% 92.2% 51.8% 40.3% 7.8%
73% 92.7% 53.3% 39.4% 7.3%
74% 93.2% 54.8% 38.5% 6.8%
75% 93.8% 56.3% 37.5% 6.3%
76% 94.2% 57.8% 36.5% 5.8%
77% 94.7% 59.3% 35.4% 5.3%
78% 95.2% 60.8% 34.3% 4.8%
79% 95.6% 62.4% 33.2% 4.4%
80% 96.0% 64.0% 32.0% 4.0%
81% 96.4% 65.6% 30.8% 3.6%
82% 96.8% 67.2% 29.5% 3.2%
83% 97.1% 68.9% 28.2% 2.9%
84% 97.4% 70.6% 26.9% 2.6%
85% 97.8% 72.3% 25.5% 2.3%
86% 98.0% 74.0% 24.1% 2.0%
87% 98.3% 75.7% 22.6% 1.7%
88% 98.6% 77.4% 21.1% 1.4%
89% 98.8% 79.2% 19.6% 1.2%
90% 99.0% 81.0% 18.0% 1.0%
91% 99.2% 82.8% 16.4% 0.8%
92% 99.4% 84.6% 14.7% 0.6%
93% 99.5% 86.5% 13.0% 0.5%
94% 99.6% 88.4% 11.3% 0.4%
95% 99.8% 90.3% 9.5% 0.3%
96% 99.8% 92.2% 7.7% 0.2%
97% 99.9% 94.1% 5.8% 0.1%
98% 100.0% 96.0% 3.9% 0.0%
99% 100.0% 98.0% 2.0% 0.0%

Note: Odds are calculated as a non-cumulative binomial probabability distribution.