That reasoning only works if all members are still willing to mate. What if the remaining species are heart broken/distraught/ect and unwilling to mate? Do we force them to mate? How do our values and ideals change when this occurs? Do they change at all?

When we imagine this apocalyptic doom of population, and mankind, we imagine a perfect world in some much that we think everyone will breed with everyone. Some men my have a problem(ED), some women may not be able to bare children(thus the creation of fertility gods), and some-be it male or female- may not want to "do it" period(homosexuality). We may also still hold old world values/moral beliefs, such as monogamy, dear.

The quote posted by Obiterdictum[1] from Orwell, one of my favorite writers, is very intriguing to me. The part that stands out the most is:

''But this is a fallacy based on the notion that human beings can be bred like animals.'' -One the topic of utilitarianistic gender values

Animals in captivity are usually force breed to maintain a linage or specific trait. Animals can build emotional bonds, however, in the wild we see very few mammal species that follow the same guidelines we find social acceptable[2]. For us to believe that every male will mate with every female we must also believe that every female will mate with every male, and vica versa.

Part of monogamy is breed into our subconscious, part is based on proximity, part is due to social context, and part is, well, emotional[3]. There are countless stories of widows never marring after their husbands are gone[see Penelope in The Odyssey]. We, many of us, enjoy monogamous relationships. Something about them brings us a joy that is very hard to put a value on. We can be tricked into them, stockholm syndrome, we can even be forced into them, rape, but we can rarely artificially create them, Truman show.

We must also asses the value of monogamous relation ships versus open relation ships(I am sorry I do not know the proper word for it); thinking that everyone will value them the same. I do not have enough data to pass judgment, although, the animal kingdom does seem to be doing well for itself ;).

Then we have to break down the proper breeding matrices. No one has said anything about age distribution in population. So are we assuming all the males/females too young/old to breed died OR are we not including them in the first count? To inspire discussion I will say we never included them in the first count...but then the situation doesn't really work as we have a new generation coming of age at some point; a boost if you will. Hypothetically, using the example given with a population size 150(aftermath) we are left with 100 women and 50 men. Breeding can be done in at least 1 day; a week at the utmost. Now those women are taken pretty much out of commission at the ~7,8,9 month. That leaves 100 women more vulnerable to starvation, illness, miscarriage, death giving birth. We also do not have the number of still births. What is the status of food? How did this population destruction occur? Too many variables.

For every perfect scenario there exists an imperfect one just as likely to occur as the latter. No person, be it male or female, is more valuable because they were born with a functioning set of genitalia. Value is always in the eye of the beholder[see currency, trade, marketing].

[1] http://news.ycombinator.com/item?id=1635248

[2]http://www.trinity.edu/rnadeau/fys/barash%20on%20monogamy.ht...

[3] http://www.csulb.edu/~kmacd/346monogamyAnimals.html

[4]http://www.mythweb.com/odyssey/book01.html#notes5back

I had to edit and remove some of my comment as it became more of a rant than an acceptable comment. The tl;dr version is, we are all different and thus behave differently. Some may be more willing to breed for the sake of it while others not so much, however, we can all be conditioned so that we are prepared for such a situation. I am not condoning this. I feel that place male and female on a scale is boarding the lines of eugenics- to which I am more opposed than I am for. Some men are strong, while others are weak. Some women are stronger than a weak man. Some men are cowards, others are not. Some women are brave, others are not. Measuring strength is easy, measuring other- not so physical traits- is harder.