The "quiverfull" movement is an effort on the part of certain Christians in America to increase the influence of their religion by having as many children as possible -- as many children as the mother's body can manage -- with the idea of their own children being the most subject to further indoctrination into their belief system, so they may serve as 'arrows in God's quiver.' But there's a catch, as it turns out -- the older brother effect. The very act of giving birth to a boy, numerous studies now confirm, effects hormonal changes on the body of the mother which make her more likely to give birth to homosexual sons in the future. Blogger Rita Hao has written on this as to one particular 'quiverfull' family, the Duggars (famed for the reality TV show depicting the enormity of their family):
The Duggars! The 18-child, no-birth-control, "we'll have as many as God decides to give us" Quiverfull, fundamentalist Christian family on the Discovery Channel that everyone loves to hate! Did I mention the reason why the Duggar parents are Quiverfull believers is because they think that birth control is the same as abortion? Did I fail to mention that all the children's names begin with the letter J? (yielding names such as Jinger, Joy-Anna, and Jordyn-Grace?)

I must confess I can no longer watch this show (it was a bad combination of Mother Duggar's questionable home-schooling techniques, combined with the family recipe for Tater Tot Casserole) -- but I have totally been wondering about this: haven't studies shown that younger male children in large families are more likely to be gay? What's going to happen if one (or more) of the younger Duggar boys come out? The Quiverfulls don't appear to be very gay-friendly.
The Duggars are only one example of such families, but are a useful sample for examination, now being a 19-child family -- a brood which includes ten dudes. Since various studies suggest that each older brother increases the chance of the next one being gay -- by 28–48% -- that youngest Duggar male with his nine older brothers (as well as five older sisters, who apparently don't much weigh on his chances) is somewhere between 2.5 and 4.3 times more likely to be gay than your average dude. Naturally, each of his nine brothers shares some population-proportionate chance of being gay, increasing by birth order, so the overall chance of at least one of the ten male Duggar children being gay is between 119 and 194 times the chance of any single average person being gay. And what is that chance? Well, no one really knows for sure, given the strong societal pressures in some regions preventing gay people from self-identifying. But in the USA as a whole, some 3.5% of the population is openly gay, while estimates of the actual gay population typically run up to about 11% -- meaning that in the case of the Duggars (and, really, any family which has ten sons, no matter the number of daughters), the probability of one of those younger boys being gay actually well exceeds the probability of all nine being straight by somewhere between a minimum of 92% and a maximum of 486%.

And so, considering that fundamentalist Christian families striving to pour more sons onto the Earth to carry forth their "values" (quite often including the condemnation of homosexuality), one can only hope that they will find a way to love and accept their many, many gay children. Perhaps, indeed, given the progressing views of the Millennial generation, perhaps a wave of gay quiverfull children is the perfect tool to change this attitudes of fundamentalist Christians once and for all.


May 2015 update: It is pointed out to me at this juncture that another sort of statistical probability has come to the fore, with one of the 19 Duggar children recently being revealed as having been a child molester (though only in his youth, so far as anybody knows at this point, and with his efforts directed mostly against his own younger sisters). Notably, this is the oldest boy, so one not statistically predisposed to homosexuality by the "older brother effect."