LAUSR

Blanchard’s (2017) latest meta-analysis pertaining to male sexual orientation and the fraternal birth order effect (FBOE) ends with the following observation: ‘‘the simple fact of the FBOE’s existence... seems beyond doubt at this point.’’While the existence of the FBOE may be beyond peradventure, there remain manydoubts, notonly about theunderlyingmechanism of the FBOE, but also about the particular sexual trait to which late fraternal birth order has the most direct correlation. Blanchard’s meta-analysis points to two correlations: (1) a very strongcorrelationbetweennumberofolderbrothersandhighly feminine gender expression among androphilic chromosomal males and (2) a weaker, yet reliably measurable, correlation between number of older brothers and androphilia among cisgender chromosomal males. The penultimate sentence of the meta-analysis suggests thatdiscovery of themechanismunderlying the FBOE may well offer insights as to why the effect is more prevalent among transgender androphilic chromosomal males than among cisgender androphilic males. I respectfully suggest that a more efficient way of finding the answer to that puzzle might be to identify a third female-typical trait—a trait other than androphilia or highly feminine gender expression— thatismoreprevalentamongtransgenderandrophilicmalesthan among cisgender androphilic males, and that is more prevalent among cisgender androphilic males than among cisgender gynephilic males. In short, it may well be that the correlations between late fraternal birth order and androphilia and between late fraternal birth order and feminine gender expression are statistical artifacts of a more direct correlation between late fraternal birth order and a third trait, a trait that I call volvivity. TheconceptofvolvivityarisesoutofagapintheEnglishlexicon that Money (1982) sought to address 35 years ago. While the English language has words to describe the separate behaviors of female and male rats and other lower mammals during heterosexual copulation—‘‘lordosis,’’‘‘presenting,’’‘‘mounting,’’ etc.—the English language does not have verbs that describe the separate actions of each of two humans engaging in penile–vaginalorpenile–analcopulation(Money,1982). Ihaveproposedthe neologisms to volv, volvive, and volvivity as the verb, adjective, andnoun, respectively,associatedwith themotoreroticbehavior of the receptive partner of a copulating human pair (Wampold, 2017). (These neologisms were derived from the Latin infinitive volvere, which means to envelop or to wrap up; Whitaker, 2010). For the reciprocal concept, I have proposed to inrump, inrumptive, and inrumptivity as the verb, adjective, and noun associated with penetrative copulatory behavior. (These neologisms were derived from the Latin infinitive inrumpere, which means to penetrate; Whitaker, 2010). Wampold (2017) provided evidence that: (1) volvivity is the female-typicaltrait thatismostdirectlyrelatedtotheFBOE,and (2) the FBOE’s links to androphilia and to highly feminine gender expression are reflections of the statistical correlations between volvivity and androphilia and between volvivity and femininegenderexpression.Wampoldconductedafraternalbirth order study that employedananal-erotic roleorientation (AERO) lens, in lieuof the traditional sexualorientation lens. Inmostcommunitiesofmen whohave sexwith men (MSM), there areat least two well-recognized AERO—bottom and top—with bottoms mostly taking the receptive/volvive intercourse role and tops mostly taking the penetrative/inrumptive role (Cardoso, 2005). MostNorthAmericanandWesternEuropeanMSMcommunities This comment refers to the article available at doi:10.1007/s10508-0171007-4.