By DAVID NG

LIESL: Why is it that we can all sing very well?

GENETICIST: Liesl, that is an excellent question! And essentially one that boils down to the classic debate of nature versus nurture. Are your genes responsible for this particular talent, or has it more to do with your upbringing? Looking at this scenario objectively, I would have to say that it is both. There have been reports that the ability to have perfect pitch—that is the ability to distinguish musical notes without points of reference—is a hereditary phenomenon, thereby strongly suggesting a genetic basis. This would seem to be supported by your father’s musical talent as well. Of course, you’ve also had the benefit of being tutored by your wayward novice governess with all-world pipes, Maria.

In conclusion, like most things pertaining to our individuality, we are influenced by both our biology and our surroundings.

GRETL: I think Liesl is very beautiful. Why am I not as pretty?

GENETICIST: Assuming no mutational errors occur during the production of sperm and egg cells, there was approximately a 1-in-70,000,000,000,000 chance that you would have been an identical clone of your sister. If you included the multitude of mutational and regulatory events that ensue during this process, that statistic would escalate to an even smaller chance that is, quite frankly, unfathomable to calculate. How did I get to this absurd number? Well, one must realize that your genetic instructions are housed as a collection of 23 pairs of chromosomes (i.e., 46 in all). In other words, it is correct to say that each human has two sets of instructions—one given to you by your father, and one by your mother. If you keep in mind that your parents themselves also have 23 pairs of chromosomes, and you realize that the child may receive only one from each pair, the likelihood of siblings having the same 46 chromosomes is the fantastic number mentioned above.

However, Gretl, do not fret. You are the youngest of the lot and still have a good chance to blossom into a stunning flower like your sister Liesel. Furthermore, cosmetic surgery these days I hear is quite impressive. And then there is always the chance of Liesl having a disfiguring accident—I hear she may be a Nazi sympathizer, which is never a good thing.

FRIEDRICH: Yes, Liesl is hot. Sometimes, even I have feelings for her. Why is it bad for me to feel that way?

GENETICIST: Incestuous relationships, as well as being frowned upon by most of society, are also disadvantageous from a biological point of view. In the genetic world, diversity breeds fitness. One example is to imagine the following. You have a set of genes that determine the ability of your immune system to recognize and combat various pathogens. Your sister Liesl also has a set of genes that do the same thing. And because you and your sister come from the same genetic pool (you have the same parents), Liesl’s immunity is quite likely to be similar to yours. Do you not see that the net effect of this is that you would create offspring with a limited repertoire of immune-system genes? Compare that to your having a child with, say, Marcia from The Brady Bunch, and you will note that this union will create offspring that have the benefit of a wider genetic pool (your parents and Marcia’s parents), thereby allowing your children to acquire a more diverse and fitter immune system.

Also, dude, she’s your sister.

BRIGITTA: Why do all of our siblings have blondish hair and blue eyes, whereas Marta and I have dark hair and dark eyes?

GENETICIST: You are thinking, perhaps, that your mother was a whore? It is true that the disparity in your outward appearances is a mite unusual. However, there is no reason to believe that any adultery has occurred. Here is the reason why. Although it is generally thought—though not confirmed—that extreme blondness (as in the case of Louisa and Friedrich) has a recessive distribution, there are numerous factors that can account for your instances of dark hair and dark eyes. First, hair and eye color are very subjective terms. Is Greta or Kurt blond, dirty blond, or strawberry blond? Genetic characterization is very difficult when the observational characterization is less than strict. Second, the pigmentation of hair is normally attributed to melanin levels, which have been shown to vary greatly during different stages of a person’s life. You may have noticed, for example, that a person’s childhood hair color tends to be lighter than their adult hair color. Third, the amount of melanin that an individual produces is influenced in part by their environment. For instance, melanin acts to protect the person from the damaging effects of the sun’s radiation. In conclusion, I do not feel that there is anything to worry about. Besides, you did not mention Liesl, who herself has dark hair. Did you omit her because you are secretly jealous of her hotness?

KURT: I think I might want to be with another boy. Is this to do with my DNA?

GENETICIST: Unfortunately, the answer is currently unknown. There have been numerous reports that have tried to implicate specific genetic regions to homosexual behavior, but presently those studies, although titillating, are at best only an indication that there is a hereditary factor for this type of sexual orientation. However, there is an abundance of ongoing research in this area, particularly with homosexual men. If you are interested, perhaps you could participate in the scientific process. Of course, it is important to remember that the Nazis do not dig gay people.

LOUISA: Why doesn’t anybody remember who I am?

GENETICIST: Alas, it appears that this is because you are the second child. I would not be surprised if there are very few pictures of you. It is not, I assume, because your parents did not love you, but simply a facet of being born after the initial excitement and newness of parenthood has passed. This, of course, has nothing to do with genetics. In order to be taken more notice of, you could try different fashions, or perhaps a new haircut. In truth, Liesl could probably give you better advice, as I am, sadly, only a geneticist.

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Originally published at McSweeney’s