What follows is an “autobiographical” note provided by the author:
“Professor Koniphorous Swamp is a vegemagus, an extremely rare type of magical person who can at will turn into a plant. As a result of this unusual ability, Prof. Swamp has devoted her career to the investigation of the biology of magic, Transfiguration in particular. She theorizes that there may be many undiscovered vegemagi, particularly among witches with botanical names such as Lavender, Lily, Myrtle, Narcissa, Olive, Pansy, and Poppy.”
Also note: it is not certain that none of the Hogwarts teachers have children, as there are no positive statements to that effect in the canon. However, it is certainly the case that there are no positive statements of the converse; that is, the canon does not rule out the childlessness of teachers at Hogwarts.
I read with interest the essay “Magic, Genes, and Pure Blood,” by glamourousgeek, being myself involved in research into the complex inheritance of magic, but I must take exception to the science expressed within it.[*] Even if the magic trait is inherited through Mendelian genetics (which does not quite seem to be the case), this argument is flawed. Purity does not and never will equal survival. Support of genetic purity is based on emotion (usually a negative emotion such as superiority which eventually breeds hatred and fear), and not on logic or science. Let me explain why.
The argument is made that intermarriage with Muggles could pose a threat to the wizarding gene pool, but this is not possible. An allele can not be “watered down” by outcrossing. An allele does not care if it is in a half-blooded (heterozygous) or pure-blooded (homozygous) individual. In fact, the way to make the most of a dominant allele (such as magic is proposed to be in the essay) is to have all individuals heterozygous rather than homozygous, as then there will be twice as many individuals in the next generation with that trait for a given number of alleles. In that case society would have to be inclusionary; you must be willing to embrace those heterozygous individuals and not see them as inferior simply because they have only one gene.
An emphasis on purity in contrast is exclusionary and selective, and in the long run is counterproductive to insuring the survival of the magic allele. It will actually serve to reduce the number of magic alleles, as it discriminates against heterozygous and even homozygous people with a Muggle grandparent. A person who has a lot of magic talent but who is not considered to be “pure” would be an outcast, shunned or worse, as he or she would be considered inferior. Even more terrible, the purists wear blinders and can not see the person beyond that one trait. Thus, an individual who lacks magic is considered subhuman, even if they possess other desirable characteristics such as intelligence, artistic skill, honesty, or courage. This attitude is distinctly unhealthy for the gene pool as a whole.
The only way to insure survival of the magic trait is to have the percentage of the magic allele in the population be maintained or increased from one generation to the next. And that is precisely where the magic community has fallen down. Magic families seem to have very few children, or none at all. Take the school staff as an example: none of the teachers have children,[**] and these are among the most gifted wizards and witches of all.
The members of the purity movement, who should understand this, are just as bad. The leader of the movement (Voldemort) has no children, resulting in his one magic allele dropping to zero after his death, although he has been trying his best to delay the inevitable. His right-hand man (Wormtail) similarly will leave no offspring, and thus no magic alleles. His lead supporter (Lucius Malfoy) has one child, which means that the four alleles he and his wife have will drop to two.
And even worse, the pure-blood fanatics have been responsible for even greater losses, as their irrational focus on purity has been responsible for the deaths of other wizards and witches. For example, the Potter family went from three magic alleles to at most two, the Longbottom family from four alleles to two. They were also responsible for eliminating the last two of the Black family, resulting in the loss of four more alleles. At the same time that the Muggle population is increasing, the magic community is responsible for killing themselves off, either literally or by attrition, at least partly through insistence on purity.
There appears to be only one group that is doing its best to increase the number of alleles in the next generation. Ironically, it is the “blood traitors” the Weasleys who are showing the way to save the magic community. By having seven children, they have gone from four magic alleles to fourteen in one generation. The Weasley family recognizes that love and peaceful co-existence is the only way to survive, and they have actively worked toward that end. Almost certainly this attitude of fostering tolerance and understanding among all people, magic and non-magic, has contributed to the success of their large and flourishing family.
If the magic community wants to survive, it will have to follow the lead of the Weasley family and not those who are trying to purge the impure. We have been told many times that love is stronger than dark magic, and it is truly only love that can save this community. It is not the blood traitors, half-bloods, and Muggle-borns who need to understand the other side; if the wizard world is to survive, the other side must come to understand what it means to love.
The footnote for the author's biographical note has been moved into the body of the first paragraph of the essay from it's original location on the author name at the beginning of the essay.