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The Sex-Balancing Act


By Roger E. Lyons
Originally appeared in Owner Breeder journal April, 1998

        Much is being said and written these days about how important it is for a breeder to select a stallion that duplicates an important ancestor of the mare through a strain of the sex opposite that contributed by her. Discussion of this does not focus on the specific contributions of the strains or even on their importance and level of influence in the breed. It is purely and simply about gender. The expression “sex-balanced inbreeding” implies that, by virtue of the gender difference of the strains, the influence of the ancestor descending through them is made whole in the new individual.
       The idea that the sexes complete one another is a powerful idea in the realm of human interaction. It underlies mainstream beliefs about, and expectations of, both romantic love and marriage. But, even in that context, one’s sense of completion depends upon qualities and traits that are expressly human, many of which may be unrelated to gender. In order to assess the claims of those who advocate sex-opposite inbreeding, we must first understand the nature and limitations of gender.
       In his Metaphysics of Love of the Sexes, Schopenhauer, writing in the 19th century, points out the irony that, while marriages are traditionally arranged around the similarities between mates, the most passionate attractions are rooted in differences. Marriages are circumscribed by ethnic, social, and even familial boundaries, but the natural affections impel us towards persons whose particular characteristics are opposite our own. Nature plays this trick on our most sacred social unit, he argues, because species survival depends upon the reconciliation of opposite qualities. Our hearts, wanting to go on, know instinctively that the best offspring result from the richest possible variety of human factors.
       Even if you are convinced that, despite all of the emotional and biological ambiguities of its expression, gender difference is crucial to both the social conventions of marriage and the natural affections that determine sexual attraction, you must still admit that gender difference alone cannot explain either of these, nor can gender difference alone explain why these social conventions and natural affections are so often in conflict with one another. Schopenhauer explains that, while social conventions impel us toward those who are similar to ourselves, the natural affections--grounded in the “will to life” of the species--forcibly draw us to others whose traits we lack. That is, as fundamental as gender difference may be to reproduction and even attraction, it has no meaning as a function of human action and relations outside a context of specific traits and qualities that are expressly human.
       Thoroughbreds do not choose their mates by way of natural affection. Their assignations are arranged, and most breeders know that there is more to a proper mating than gender difference. Advocates of sex-opposite inbreeding would not argue that gender difference is a sufficient reason to breed a given mare to a given stallion. Yet, when it comes to combining two ancestors several generations removed--ancestors who happen to share at least one parent--this is precisely what they argue.
       The doctrine of sex-opposite inbreeding is founded on a metaphysical principle. The mythological expression of this principle has it that the sexes once constituted an androgynous body, but were separated, after which each then sought completion in the other. How this metaphysical principle manifests itself in human life depends for Schopenhauer on particular human traits.
       The advocates of sex-opposite inbreeding do not take this step. They are content to assume that gender difference itself is a sufficient cause of affinity between thoroughbred relatives. By comparison with the metaphysics of Schopenhauer, that of the advocates of sex-opposite inbreeding is found wanting. They err in treating sex opposition as a qualitatively determinative function of inheritance when, in fact, it is only a necessary condition of reproduction.
       What about the empirical ground? First, let's not confuse the situation by referring to sex-opposite inbreeding as the more general "balanced inbreeding." The first order of empirical research is to set aside all presumption. If there is another way to balance inbreeding, other than by combining strains of opposite sex, then referring to sex-opposite inbreeding as "balanced inbreeding" represents a part as the whole and thereby suppresses other possible methods. It also, in every case, begs the question of what--that is relevant to the thoroughbred in particular-- might be placed in balance. Empirically, the term "balanced inbreeding" assumes what has not been confirmed--that something of substance is balanced through strains of opposite sex. In Schopenhauer's metaphysics, the particular traits are crucial.

An empirical study
       Several years ago, after reading Harold Hampton’s first two accounts of sex-opposite inbreeding, which were offered with an almost irresistible conviction, I undertook a populational study designed to test his most fundamental claim: that sex-opposite inbreeding has an absolute value. The results did not confirm that claim, but I did not then consider the matter to be of much importance. Since then, advocacy of this claim has grown and with it the need for an empirical accounting.
       My study compared the frequency of occurrence of sex-opposite inbreeding in a sample of 1,000 low-performing 1988 and 1989 Keeneland September yearlings with the frequency of occurrence in the population of 1,853 G1-2 winners worldwide for the years 1990-94. The nearest and then the next occurrence of inbreeding (to a different ancestor) in each ancestry back through the sixth generation were surveyed. Now, the advocates of sex-balanced inbreeding frequently extend their interpretations back to many generations removed. I would submit that, if sex-balanced inbreeding has a favorable value, regardless of ancestry (an important qualifier, as we shall see), then it should show up in this study. After all, if very distant oppositions have an effect, then the very nearest ones should, too. Even if distant oppositions are deemed more relevant than closer ones in some ancestries, for reasons that escape this researcher, the nearest occurrences should have an effect strong enough to be noticeable in large samples.
       This study did not assume that inbreeding through mixed-sex strains balances anything in particular. Again, the idea that one sex completes the other qualitatively is a metaphysical principle that inevitably found mythological expression. But it does not constitute a legitimate practical argument. Marking occurrences of sex opposition as such in ancestries devolves from the same intellectual commitment as plotting an astrological chart or counting yarrow stalks in preparation for a reading of the I Ching. The main distinction is that these oracular media have a much richer interpretive tradition.
       Readers of Harold Hampton’s third volume, published posthumously by B. Spooner C.A., PO Box 106-072, Auckland, New Zealand, and assembled from tape recordings by Hampton’s countryman, Clive Harper, will note that oracular elements figure prominently in Hampton’s method. His insistence upon transcribing ancestries by hand, as a mnemonic and intuititional aid, has much in common with the ritual practices associated with oracular consultation. Like other oracular forms, his approach is mainly concerned with prophecy. He takes as his empirical ground a study conducted in the 1950s, which consisted in predictions of future performance of auction yearlings based on a prior analysis of inbreeding. This research design is acceptable when definite rules of analysis are used to identify the object of study, but Hampton’s approach to pedigree interpretation is unsystematic and quite often obscure. As a result, his approach has much more in common with oracular interpretation than with a scientific methodology that would deal in probabilities.
       Significant genetic variables may affect the outcomes of sex-opposite inbreeding under certain conditions, but the public understanding is that using strains of opposite sex improves ancestries by balancing the male and female principles as such. In order to address precisely this interpretation, I instructed the computer to record occurrences of inbreeding involving mixed-sex strains to see how the frequency in a group of auction yearlings that subsequently performed at a low level compared with a group of G1-2 winners. The computer dutifully placed each occurrence of inbreeding into one of three groups: all-female strains, all-male strains, and mixed-sex strains. If you believe that there is an advantage to using mixed-sex strains, then you would expect them to occur more frequently in the G1-2-winning group than in the auction group.
       The results of the survey are represented in Tables I and II. The parenthetic p1 and p2 represent the proportions for each data item surveyed in the G1-2 winners and the auction group, respectively. Advocates of sex-opposite inbreeding are invited to do whatever business with this information that they please, but, for my money, there is not a dime’s worth of difference between the frequency of mixed-sex strains in the G1-2-winning group and the frequency in the auction group at any level. Right down the line the proportions of mixed-sex strains are virtually equal between the two groups.
       However, one might argue in favor of about two cents worth of difference in the following comparisons from Table I, which proved to have very slight statistical significance:

       1. Inbreeding to a male ancestor through all-female strains proved slightly unfavorable, whether in the nearest or the next occurrence of inbreeding; and the use of all female strains in the second occurrence of inbreeding proved unfavorable among male and female ancestors combined.

       2. Inbreeding to a male ancestor through all-male strains proved slightly favorable as the second occurrence of inbreeding; and the use of all-male strains proved slightly favorable among male and female ancestors combined.

The use of mixed-sex strains showed no statistically significant advantage with respect to either male or female ancestors in either the nearest or next occurrences. Slightly significant effects are also noted in Table II:

       1. The use of same-sex strains in both the first and second instances of inbreeding, regardless of the sex of the ancestor, proved slightly unfavorable.

       2. The use of mixed-sex strains in one, but not the other, instance of inbreeding, regardless of the sex of the ancestor, proved slightly favorable, but whether it occurred in the first or second occurrence made no difference.

But I would emphasize that all of these effects were so slight as to be dubious at best.
       Most, if not all, of the effects noted are probably related to the unfavorable effect of using all-female strains. This need have nothing to do with gender per se, but more likely with the fact that female strains in thoroughbred ancestries are, on the whole, inferior to male strains. This would tend to suggest that it is folly to use just any female strain for the sake of mixing the sex of strains. In any event, these effects fall far short of justifying the importance that has been attributed to the use of strains of opposite sex.

       The results of this study deliver a knock-out punch to the idea that inbreeding through strains of opposite sex has an absolute value regardless of the ancestry involved. To be sure, this breeding method may have favorable effects on certain ancestries and unfavorable effects on others, in which event those cases would establish a point of balance in a study that does not discriminate between ancestries, such as the one presented here. If a majority of important ancestors, or even the most important ones, were favorably subject to sex-opposite inbreeding, then we would expect the balance to tilt in favor of this breeding method in such a study. Even if that were the case, it would be a mistake to attribute such measurable effects to gender difference, per se, in the strains, especially since no adequate theoretical grounds on which to base such effects have been put forward.
       Some ancestors, but not all, may indeed contribute through their sons and daughters in a way that enables their influence to be redeemed with sex-opposite inbreeding. But this brings us back to the question, What is there to balance through the strains? If we set aside the matter of gender difference, then we must follow Schopenhauer in the direction of individual differences that matter, in particular, to the thoroughbred.
       Gender difference, though irrelevant, per se, to the issue of balance, may appear to be relevant in cases of some ancestors whose superior colts happened to differ in typologically relevant ways from the superior fillies. Hampton, in his initial exposition, came close to this when he incorrectly surmised in passing that stallions contribute stamina and mares speed. Apart from this, he missed what Schopenhauer took for granted: that, beyond its role in reproduction, including the genetic regularities that pertain to it, gender is an empty vessel. He also missed Varola’s point that speed and stamina are only the surface features of thoroughbred typology.
       Of all of the breeding methods that might step into the ring claiming dominion over all of thoroughbred breeding, there is not one that would be left standing after going a round or two with a tough empirical analysis. The variety of the thoroughbred is such that some ancestries may be subject to a given breeding method--whether it be close inbreeding, the Rasmussen factor, or whatever--while others will not be. Therefore, pedigree interpretation should not consist in the effort to discover the ways in which a given ancestry confirms a dogmatic commitment to a given breeding method (putting the cart before the horse), but rather in discovering the best breeding method to apply to the ancestry at hand. This can only be done by taking that ancestry--and not just an individual representative of it--as the object of study.

Table I: Gender of ancestors and strains as variables to inbreeding

Nearest inbreeding
				G1-2 wnrs (p1)	Auction (p2)

Female ancestor			N=70		N=35
	all-female strains	 	18 (.258)		7 (.200)
	all-male strains		26 (.371)		15 (.429)
	mixed-sex strains		26 (.371)		13 (.371)

Male ancestor			N=1768		N=965
	all-female strains		195 (.110)	137 (.142)*
	all-male strains		758 (.429)	404 (.419)
	mixed-sex strains		815 (.461)	424 (.439)

All ancestors			N=1838		N=1000
	all-female strains		213 (.116)	144 (.140)
	all-male strains		784 (.427)	419 (.419)
	mixed-sex strains		841 (.457)	437 (.437)

Next inbreeding

Female ancestor			N=111		N=59
	all-female strains		28 (.252)		14 (.237)
	all-male strains		35 (.315)		15 (.254)
	mixed-sex strains		48 (.432)		30 (.509)

Male ancestor			N=1708		N=939
	all-female strains		257 (.150)	190 (.202)*
	all-male strains		651 (.381)	310 (.330)**
	mixed-sex strains		800 (.468)	439 (.468)

All ancestors			N=1819		N=998
	all-female strains		285 (.157)	204 (.204)*
	all-male strains		686 (.377)	325 (.326)**
	mixed-sex strains		848 (.466)	469 (.470)

*Indicates a significantly unfavorable effect.
**Indicates a significantly favorable effect.

Table II: Frequency of mixed-sex stains in first two occurrences of inbreeding

			G1-2 wnrs (p1)	Auction sample (p2)
			N=1819		N=998

Neither occurrence		511 (.281)	305 (.306)*
Both occurrences		371 (.204)	212 (.212)
One or the other		937 (.515)	481 (.482)**
	First		460 (.496)	224 (.467)	
	Second		477 (.504)	257 (.533)

Copyright © 1998 Roger E. Lyons.
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