Onset of Puberty in MZ and DZ Twins

1977 ◽  
Vol 26 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Siv Fischbein
Keyword(s):  
Twin Study ◽  
Genetic Factors ◽  
Genetic Regulation ◽  
Peak Height ◽  
Sex Characteristics ◽  
Age At Menarche ◽  
Secondary Sex Characteristics ◽  
Maximal Height ◽  
Peak Weight ◽  
Weight Velocity

A twin study on the significance of genetic factors for the variation in peak height and peak weight velocity, as well as in age at menarche and the development of secondary sex characteristics, is presented. Evidence of a rather strong genetic regulation of the occurrence of puberty was obtained in the analysis. The maximal height or weight gain (in cm/year or kg/year) seems to be, at least in girls, less influenced by genetic factors than the age at which it appears.

scholarly journals The effect of early growth patterns and lung function on the development of childhood asthma: a population based study

Thorax ◽  
2018 ◽  
Vol 73 (12) ◽  
pp. 1137-1145 ◽  
Author(s):  
Maribel Casas ◽  
Herman T den Dekker ◽  
Claudia J Kruithof ◽  
Irwin K Reiss ◽  
Martine Vrijheid ◽  
...  
Keyword(s):  
Lung Function ◽  
Childhood Asthma ◽  
Vital Capacity ◽  
Population Based ◽  
Peak Height ◽  
Growth Patterns ◽  
Current Asthma ◽  
Childhood Growth ◽  
Peak Weight ◽  
Weight Velocity

BackgroundInfant weight gain is associated with lower lung function and a higher risk of childhood asthma. Detailed individual childhood growth patterns might be better predictors of childhood respiratory morbidity than the difference between two weight and height measurements. We assessed the associations of early childhood growth patterns with lung function and asthma at the age of 10 years and whether the child’s current body mass index (BMI) influenced any association.MethodsWe derived peak height and weight growth velocity, BMI at adiposity peak, and age at adiposity peak from longitudinally measured weight and height data in the first 3 years of life of 4435 children enrolled in a population-based prospective cohort study. At 10 years of age, spirometry was performed and current asthma was assessed by questionnaire. Spirometry outcomes included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio, and forced expiratory flow after exhaling 75% of vital capacity (FEF75).ResultsGreater peak weight velocity was associated with higher FVC but lower FEV1/FVC and FEF75. Greater BMI at adiposity peak was associated with higher FVC and FEV1 but lower FEV1/FVC and FEF75. Greater age at adiposity peak was associated with higher FVC, FEV1, FEV1/FVC and FEF75, particularly in children with a small size at birth, and lower odds of current asthma in boys. The child’s current BMI only explained the associations of peak weight velocity and BMI at adiposity peak with FVC and FEV1. Peak height velocity was not consistently associated with impaired lung function or asthma.ConclusionPeak weight velocity and BMI at adiposity peak were associated with reduced airway patency in relation to lung volume, whereas age at adiposity peak was associated with higher lung function parameters and lower risk of asthma at 10 years, particularly in boys.

scholarly journals Women’s Preferences for Strong Men Under Perceived Harsh Versus Safe Ecological Conditions

2021 ◽  
Vol 19 (3) ◽  
pp. 147470492110323
Author(s):  
Ray Garza ◽  
Farid Pazhoohi ◽  
Jennifer Byrd-Craven
Keyword(s):  
Ecological Factors ◽  
Ecological Condition ◽  
Sex Characteristics ◽  
Ecological Conditions ◽  
University Women ◽  
Secondary Sex Characteristics ◽  
Trade Offs ◽  
Forced Choice Task ◽  
Women’S Preferences ◽  
Physical Features

Ecological conditions provide information about available resources for one’s environment. In humans, this has been shown to influence reproductive behavior, as individuals may engage in trade-offs between partner quality and investment. For instance, many women may trade-off preferences for men with physical features indicative of social dominance and health over physical features indicative of commitment and investment. The current study explored women’s preferences for formidable men under safe vs. harsh ecological conditions. Across three studies, U.S. university women ( N = 1,098) were randomly assigned to a perceived harsh or safe ecological condition. They were asked to rate the attractiveness of men’s body types (i.e., muscular vs. less muscular). Findings revealed that in general, women rated stronger men as more attractive than weaker men irrespective of the ecological condition. Evidence for preference as a function of ecology appeared only when a two-alternative forced-choice task was used (Study 3), but not in rating tasks (Studies 1 and 2). Study 3 showed that women had a relatively stronger preference for stronger men for short-term relationships in a resource scarce ecological condition. This research provides some evidence that perceived ecological conditions can drive women’s preferences for men with enhanced secondary sex characteristics as a function of mating context. These findings are consistent with previous research indicating the importance of physical characteristics in men’s attractiveness, and it adds to the existing literature on ecological factors and mating preferences.

scholarly journals The Role of Genetic Factors for Hearing Deterioration Across 20 Years: A Twin Study

2015 ◽  
Vol 70 (5) ◽  
pp. 647-653 ◽  
Author(s):  
Renata Bogo ◽  
Ahmed Farah ◽  
Ann-Christin Johnson ◽  
Kjell K. Karlsson ◽  
Nancy L. Pedersen ◽  
...  
Keyword(s):  
Twin Study ◽  
Genetic Factors

Influence of genetic factors and institutional environment on entrepreneurial activity: evidence from a twin study in Italy

2021 ◽  
Author(s):  
Diego Zunino
Keyword(s):  
Twin Study ◽  
Genetic Factors ◽  
Institutional Environment ◽  
Behavioral Genetics ◽  
Entrepreneurial Activity ◽  
Alternative Theory ◽  
Environment Interaction ◽  
Institutional Environments ◽  
Gene Environment Interaction ◽  
Gene Environment

Abstract Genetic factors influence entrepreneurial activity, but we know little about how genetic factors influence entrepreneurial activity when the institutional environment is favorable. Two theories from behavioral genetics explain the gene–environment interaction. One theory argues that a favorable environment favors the development of genetic factors and their influence. An alternative theory posits that unfavorable environment triggers the development of genetic factors and their influence. I test these two competing theories with a twin study based in Italy. I compare the influence of genetic factors in provinces where the institutional environment favors entrepreneurial activity with provinces where the institutional environment is unfavorable to entrepreneurial activity. I found consistent evidence that genetic factors exert a larger influence in favorable institutional environments, suggesting that favorable institutional environments complement genetic factors.

The Nature and Origin of Common Phobic Fears

1979 ◽  
Vol 134 (4) ◽  
pp. 343-351 ◽  
Author(s):  
Svenn Torgersen
Keyword(s):  
Environmental Factors ◽  
Social Adjustment ◽  
Twin Study ◽  
Genetic Factors ◽  
Factor Analyses ◽  
Factors Affecting ◽  
Five Factors

SummaryBy means of a twin study an attempt was made to throw light upon the aetiology and nosology of phobic fears. Factor analyses revealed five factors, namely separation fears, animal fears, mutilation fears, social fears and nature fears. The study demonstrated that, apart from separation fears, genetic factors play a part in the strength as well as content of phobic fears. Environmental factors, affecting the development of dependence, reserve and neurotic traits generally, seemed also to be of some importance. It was further demonstrated that phobic fears were related to emotional and social adjustment and this was true to an even greater extent for separation fears.

GYNECOLOGY OF CHILDREN AND ADOLESCENTS

PEDIATRICS ◽  
1958 ◽  
Vol 22 (2) ◽  
pp. 395-400
Author(s):  
John W. Huffman ◽  
Elsie Wieczorowski
Keyword(s):  
Round Table ◽  
Late Childhood ◽  
Sex Characteristics ◽  
Vaginal Mucosa ◽  
Relative Incidence ◽  
Secondary Sex Characteristics ◽  
Etiologic Agents ◽  
Special Clinic ◽  
History Of ◽  
Phases Of Development

THE DISCUSSANTS began the round table with a few general comments concerning various phases of development of the female. At birth and for the first week or more of life, the effects of maternal hormones on the newborn infant may be evidenced by hypertrophy of the breasts, prominence of the genitalia with nonpurulent vaginal secretion and occasional uterine bleeding. Throughout the remainder of infancy, until late childhood, there are no changes in the genitalia, and the mucosa of the vagina remains shrunken, producing little or no secretion. From the period of late childhood to early adolescence—that phase extending from the first menstrual period until the onset of ovulation—secondary sex characteristics develop and the vaginal mucosa undergoes cornification, becomes succulent and produces an increased quantity of secretion. Late adolescence is defined as that phase from the first ovulation to full maturity. The phases of adolescence are never clearly demarcated. Certain pathologic conditions commonly seen in female children were then described. The relative incidence of these conditions as seen in a special clinic reflects their incidence in a general pediatric practice. Nonspecific Vulvovaginitis The majority of children (75%) are referred to the gynecologic clinic because of vulvovaginitis. Of these, 75% are found to have nonspecific vulvovaginitis. Etiologic agents and their relative incidence in the remainder of patients are: monilia, 15%; foreign body, 5%; and infections due to trichomonas, gonococcus and pinworms, 5%. Children under 10 years of age are most commonly affected. Those found to have vulvovaginitis due to fungi have usually given a history of recent antibiotic therapy.

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