Biomedical subjects

A F Bogaert

Publications and source records attributed to A F Bogaert.

16 recordsLinked to original sources

PubMed2001

Handedness, criminality, and sexual offending.

A very large database was used to investigate whether men with a history of criminality and/or sexual offending have a higher incidence of nonright-handedness (NRH) relative to a control sample of nonoffender men. The sample (N>8000) comprised interviews by investigators at the Kinsey Institute for Sex and Reproduction in Indiana. The general offender group and a subsample of sex offenders (e.g. pedophiles) had a significantly higher rate of NRH relative to the control (nonoffender) men. In addition, evidence was found that the general criminality/NRH relationship might result from increased educational difficulties that some nonright-handers experience. In contrast, education was unrelated to the handedness/pedophilia relationship, suggesting that there may be a different mechanism underlying the handedness/pedophile relationship than the handedness/(general) criminality relationship. Finally, as a cautionary note, it is stressed that the effects are small and that NRH should not be used as a marker of criminality.

Adult↗

PubMed2001

Personality, individual differences, and preferences for the sexual media.

The extent to which personality and individual differences predict preferences for and choices of various forms of sexual media was examined. Personality (e.g., intelligence, aggression) and individual difference factors (e.g., prior sexual experience) were assessed in 160 undergraduate men. These men also indicated their preferences for and choices of various forms of sexual media (e.g., "erotic," female insatiability, violent). As expected, individual differences were predictive, with, for example, men lower in intelligence and higher in aggressive/antisocial tendencies having a higher preference for violent sexual stimuli than men higher in intelligence and lower in aggressive/antisocial tendencies had. In addition, as much as 50% of the variation in the preference for violent sexual materials was accounted for by an additive combination of individual differences and self-report arousal to these materials. Finally, the results indicated that, when given a choice to view different media materials, the men chose a broad range of media materials, although the "female insatiability" films were more popular than the other sexual films (e.g., "erotic" or violent). Results are discussed in relation to recent research and psychological theories that view adults as active in choosing their own social environments.

Erotica↗

PubMed2000

Fraternal birth order and sexual orientation in pedophiles.

Whether homosexual pedophiles have more older brothers (a higher fraternal birth order) than do heterosexual pedophiles was investigated. Subjects were 260 sex offenders (against children age 14 or younger) and 260 matched volunteer controls. The subject's relative attraction to male and female children was assessed by phallometric testing in one analysis, and by his offense history in another. Both methods showed that fraternal birth order correlates with homosexuality in pedophiles, just as it does in men attracted to physically mature partners. Results suggest that fraternal birth order (or the underlying variable it represents) may prove the first identified universal factor in homosexual development. Results also argue against a previous explanation of the high prevalence of homosexuality in pedophiles (25% in this study), namely, that the factors that determine sexual preference in pedophiles are different from those that determine sexual preference in men attracted to adults. An alternative explanation in terms of canalization of development is suggested.

Adolescent↗

PubMed1999

The relation between sexual orientation and penile size.

The relation between sexual orientation and penile dimensions in a large sample of men was studied. Subjects were 5122 men interviewed by the Kinsey Institute for Research in Sex, Gender, and Reproduction from 1938 to 1963. They were dichotomously classified as either homosexual (n = 935) or heterosexual (n = 4187). Penile dimensions were assessed using five measures of penile length and circumference from Kinsey's original protocol. On all five measures, homosexual men reported larger penises than did heterosexual men. Explanations for these differences are discussed, including the possibility that these findings provide additional evidence that variations in prenatal hormonal levels (or other biological mechanisms affecting reproductive structures) affect sexual orientation development.

Adult↗

PubMed1998

Birth order and sibling sex ratio in homosexual and heterosexual non-white men.

Researchers interested in the development of sexual orientation have investigated predominantly or exclusively White samples. To address this imbalance, the relations between sexual orientation and two biodemographic variables, birth order and sibling sex ratio, were examined in a sample of non-White men. The men (N = 823) were interviewed by investigators at the Kinsey Institute for Sex and Reproduction from 1938 to 1963. A significantly later birth order was observed for non-White homosexual men relative to non-White heterosexual men. Non-White homosexual men also had an elevated sibling sex ratio. Results add to the generalizability of the birth order and sibling sex ratio effects previously observed to occur in (White) homosexual men.

Adult↗

PubMed1998

Birth order in homosexual versus heterosexual sex offenders against children, pubescents, and adults.

Homosexual men erotically attracted to physically mature partners typically have more older brothers than comparable heterosexual men. We investigated whether late fraternal birth positions also occur in homosexuals attracted to children or pubescents. Probands were 710 sex offenders from Gebhard et al.'s (1965) study of sexual offending. Homosexual offenders against adults and pubescents had later fraternal birth positions than heterosexual offenders against adults and pubescents, respectively; there was no difference between the homosexual and heterosexual offenders against children. Results provide some evidence that homosexuality in men attracted to immature males is etiologically related to homosexuality in men attracted to mature males.

Adolescent↗

PubMed1997

The relation of closed birth intervals to the sex of the preceding child and the sexual orientation of the succeeding child.

The study investigated whether homosexual men are, on average, born a shorter time after their next-older siblings than are heterosexual men. Because of mixed evidence that birth intervals are longer after a male child, the sex of the next-older sibling was included as a control variable. The probands were 220 heterosexual and 183 homosexual men with at least one older sibling examined in Southern Ontario in 1994-95. These completed a self-administered, anonymous questionnaire concerning their family background and other biodemographic information. The results showed that birth interval was negatively correlated with sibship size, positively correlated with maternal age, and uncorrelated with paternal age. They also confirmed that birth intervals are longer after a male than after a female child. The mean birth intervals preceding heterosexual and homosexual males, however, were virtually identical, indicating that the association of short birth intervals with decreased sex hormone levels in cord blood is unrelated to the development of sexual orientation.

Adolescent↗

PubMed1997

Additive effects of older brothers and homosexual brothers in the prediction of marriage and cohabitation.

Research has shown that male homosexuality tends to cluster in families and that homosexual males have, on average, a greater number of older brothers than do heterosexual males. This study investigated whether the former, between-families effect and the latter, within-families effect are additive. The subjects were 717 full siblings over age 40 reported by 343 heterosexual and homosexual male probands examined in Southern Ontario in 1994-1995. The sibling's history of legal marriage or cohabitation in a heterosexual relationship was taken as a proxy variable for sexual orientation. There were no significant findings for the female siblings. As expected, the never-married male siblings were more likely to come from the sibships of the homosexual probands, and they had a greater average number of older brothers. A bootstrapped logistic regression analysis showed that an additive model best explained the male siblings' data. The results suggest that the familial aggregation of male homosexuality cannot be explained by the birth order effect and that older brothers and family membership reflect separate influences on sexual orientation or sexual orientation-correlated behavior.

Adult↗

PubMed1997

Pedophilia, sexual orientation, and birth order.

This study extended research on birth order and erotic preferences by examining birth order in a sample of pedophiles. Charts of 338 pedophiles, assessed from 1980-1994 in the Behavioural Sexology Department of the Clarke Institute of Psychiatry in Toronto, were reviewed for family-demographic information. In total, 170 (57 heterosexual pedophiles, 68 homosexual pedophiles, and 45 bisexual pedophiles) of these men had sufficient sibling information to be included in the analyses. The results indicated that homosexual-bisexual pedophiles had a later birth order than heterosexual pedophiles and that this effect was primarily the result of the homosexual-bisexual group being born later among their brothers. The results extend previous findings that homosexual men, regardless of sample composition, have a later birth order than comparable groups of heterosexual men. The results also challenge some existing theories on the nature and origins of pedophilia.

Adolescent↗

PubMed1997

Birth order and sexual orientation in women.

One of the world's largest databases on human sexuality was used to investigate whether lesbians, like homosexual men, have a later birth order relative to heterosexual comparisons. The women (N > 5,000) were interviewed by investigators at the Kinsey Institute for Sex and Reproduction from 1938 to 1963. The women were dichotomously classified as lesbian (n = 257) or heterosexual (n = 5,008). No significant birth order effect was observed. Results support theories of gender-specific mechanisms in the development of sexual orientation in women and men.

Adult↗

PubMed1997

Genital asymmetry in men.

This study examined genital asymmetry in a large sample of men. The probands were 6544 non-delinquent men who were interviewed by the Kinsey Institute for Research in Sex, Gender and Reproduction from 1938 to 1963. The measures were four indicators of penile and scrotal asymmetry, along with self-reported handedness, from Kinsey's interview protocol. Most men reported some degree of lateral asymmetry in their flaccid penis and in their testicles; less asymmetry was reported for their erect penis. The asymmetry typically occurred in the left direction, and this pattern occurred in both right- and nonright-handers. However, this 'leftward' pattern was significantly less pronounced in nonright-handers. The results are discussed in relation to previous findings of genital asymmetry in men, the possible relationship of genital asymmetry to functional cerebral asymmetry, and recent data suggesting genital asymmetry may predict patterns of cognitive performance and genital/sexual organ cancers.

Adult↗

PubMed1996

Handedness in homosexual and heterosexual men in the Kinsey interview data.

The relationship between sexual orientation and handedness in a large sample of men was examined. Subjects were 6544 nondelinquent men interviewed by the Kinsey Institute for Research in Sex, Gender, and Reproduction from 1938 to 1963. Subjects were classified as either homosexual (n = 1004) or heterosexual (n = 4579). Results failed to demonstrate a difference in handedness, with both groups having rates of non-right-handedness (i.e., 11-12%) approximately equal to establish norms. These findings do not replicate some recent studies indicating an increased level of non-right-handedness in homosexual men.

Functional Laterality↗

PubMed1996

Biodemographic comparisons of homosexual and heterosexual men in the Kinsey Interview Data.

Relations between sexual orientation and several biodemographic variables previously reported to differentiate between homosexual and heterosexual men were examined. Subjects were 4948 white, postpubertal males, who were never reared in foster homes, orphanages, or other institutions, and were never arrested or convicted on criminal charges. These were dichotomously classified as homosexual (n = 844) or heterosexual (n = 4104). Data came from survey interviews conducted by staff members of The Kinesey Institute for Research in Sex, Gender, and Reproduction from 1938 to 1963. Results extended previous findings that, compared with heterosexual controls, homosexual men have a later birth order, an earlier onset of puberty, and a lower body weight. Sexual orientation was weakly related or unrelated to height, paternal age, and sibling sex ratio. A more detailed analysis of the late birth order of the homosexual group showed that homosexual men have a greater number of older brothers than do heterosexual men, but they do not have a greater number of older sisters, once their number of older brothers has been taken into account.

Birth Order↗

PubMed1996

Volunteer bias in human sexuality research: evidence for both sexuality and personality differences in males.

The extent to which personality, social behavior, and sexuality differed in undergraduate males under two different types of recruitment, volunteer and nonvolunteer, was investigated. Nonvolunteers (N = 160) were ostensibly recruited for a study on personality, and volunteers (N = 204) were overtly recruited for a study on human sexuality. Both samples completed the same personality, social behavior, and sexuality questionnaires. Volunteers were found to be more sexually experienced, more interested in sexual variety, and more erotophilic than the nonvolunteers. In addition and contrary to most prior research, the volunteer and nonvolunteer samples also differed in personality and social behavior, with the volunteers being higher in sensation seeking and lower on measures of social conformity and rule-following behavior than the nonvolunteers. Results extend prior research suggesting limits to the generalizability of some human sexuality research.

Exploratory Behavior↗

PubMed1996

Homosexuality in men and number of older brothers.

OBJECTIVE: This study investigated whether homosexual men have a higher mean birth order than heterosexual men primarily because they have more older brothers or because they have more older siblings of both sexes. METHOD: For the main analyses, 302 heterosexual men were individually matched on year of birth with an equal number of heterosexual men. Each completed a self-administered, anonymous questionnaire concerning family background and other biodemographic information. RESULTS: Logistic regression analysis showed that homosexuality was positively correlated with the proband's number of older brothers but not with older sisters, younger brothers, younger sisters, or parental age at the time of the proband's birth. Each additional older brother increased the odds of homosexuality by 33%. CONCLUSIONS: These results restrict the range of possible theories of the birth order phenomenon to those that can explain not only why older brothers increase the probability of homosexuality in later-born males but also why older sisters neither enhance this effect nor counteract it.

Adolescent↗

PubMed1989

Population differences in susceptibility to AIDS: an evolutionary analysis.

Previously we have reported population differences in sexual restraint such that, higher socio-economic status greater than lower socio-economic status, and Mongoloids greater than Caucasoids greater than Negroids. This ordering was predicted from a gene-based evolutionary theory of r/K reproductive strategies in which a trade-off occurs between gamete production and social behaviors such as intelligence, law-abidingness, and parental care. Here we consider the implications of these analyses for sexual dysfunction, including susceptibility to AIDS. We conclude that relative to Caucasians, populations of Asian ancestry are inclined to a greater frequency of inhibitory disorders such as low sexual excitement and premature ejaculation and to a lower frequency of sexually transmitted diseases including AIDS, while populations of African ancestry are inclined to a greater frequency of uninhibited disorders such as rape and unintended pregnancy and to more sexually transmitted diseases including AIDS.

Acquired Immunodeficiency Syndrome↗