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Reproductive Toxicology (Elmsford, N.Y.) Mar 2021Concerns that the phytoestrogens (isoflavones) in soy may feminize men continue to be raised. Several studies and case-reports describing feminizing effects including... (Meta-Analysis)
Meta-Analysis Review
Concerns that the phytoestrogens (isoflavones) in soy may feminize men continue to be raised. Several studies and case-reports describing feminizing effects including lowering testosterone levels and raising estrogen levels in men have been published. For this reason, the clinical data were meta-analyzed to determine whether soy or isoflavone intake affects total testosterone (TT), free testosterone (FT), estradiol (E), estrone (E), and sex hormone binding globulin (SHBG). PubMed and CAB Abstracts databases were searched between 2010 and April 2020, with use of controlled vocabulary specific to the databases. Peer-reviewed studies published in English were selected if (1) adult men consumed soyfoods, soy protein, or isoflavone extracts (from soy or red clover) and [2] circulating TT, FT, SHBG, E2 or E1 was assessed. Data were extracted by two independent reviewers. With one exception, studies included in a 2010 meta-analysis were included in the current analysis. A total of 41 studies were included in the analyses. TT and FT levels were measured in 1753 and 752 men, respectively; E and E levels were measured in 1000 and 239 men, respectively and SHBG was measured in 967 men. Regardless of the statistical model, no significant effects of soy protein or isoflavone intake on any of the outcomes measured were found. Sub-analysis of the data according to isoflavone dose and study duration also showed no effect. This updated and expanded meta-analysis indicates that regardless of dose and study duration, neither soy protein nor isoflavone exposure affects TT, FT, E or E levels in men.
Topics: Adolescent; Adult; Aged; Diet; Dietary Supplements; Estrogens; Feminization; Humans; Isoflavones; Male; Middle Aged; Phytoestrogens; Soybean Proteins; Testosterone; Young Adult
PubMed: 33383165
DOI: 10.1016/j.reprotox.2020.12.019 -
Gland Surgery Jul 2023Gender-affirming surgery (GAS), including breast feminization, is requested and performed with increasing frequency. Transgender women may seek chest feminization... (Review)
Review
Gender-affirming surgery (GAS), including breast feminization, is requested and performed with increasing frequency. Transgender women may seek chest feminization surgery to address gender dysphoria, and such procedures have been shown to increase psychosocial and sexual well-being. Despite the potential effects of hormone therapy and androgen blockade on breast development, the results of glandular growth in adult transgender women are typically disappointing and are often inadequate to achieve the patient's goals. When evaluating options for breast construction, an implant-based approach meets the needs of most patients. However, patient choice, implant complications, acquired and congenital alterations of chest anatomy and the unique challenges of feminizing a natal male chest occasionally require consideration of other options. We review the few cases of gender-affirming breast reconstruction using autologous tissue published in the literature and summarize the senior author's approach and technique. We also review two cases of autologous chest feminization by the senior author. Ultimately, while implant-based reconstruction should continue to be the default procedure and offered to the majority of patients, several factors need to be considered when determining the optimal approach to breast feminization for a given patient. In patients with congenital or acquired deformities or a variety of factors where a reasonable outcome cannot be achieved with implants, autologous reconstruction should remain an option.
PubMed: 37727344
DOI: 10.21037/gs-23-133 -
International Journal of General... 2020Voice feminization for transgender women is a highly complicated comprehensive transition process. Voice feminization has been thought to be equal to pitch elevation.... (Review)
Review
Voice feminization for transgender women is a highly complicated comprehensive transition process. Voice feminization has been thought to be equal to pitch elevation. Thus, many surgical procedures have only focused on pitch raising for voice feminization. However, voice feminization should not only consider voice pitch but also consider gender differences in physical, neurophysiological, and acoustical characteristics of voice. That is why voice therapy has been the preferred choice for the feminization of the voice. Considering gender difference of phonatory system, the method for voice feminization consists of changing the following four critical elements: fundamental frequency, resonance frequency related to vocal tract volume and length, formant tuning, and phonatory pattern. Voice feminizing process can be generally divided into non-surgical feminization and surgical feminization. As a non-surgical procedure, feminization voice therapy consists of increasing fundamental frequency, improving oral and pharyngeal resonance, and behavioral therapy. Surgical feminization usually can be achieved by external approach or endoscopic approach. Based on three factors (length, tension and mass) of vocal fold for pitch modulation, surgical procedure can be classified as one-factor, two-factors and three-factors modification of vocal folds. Recent systematic reviews and meta-analysis studies have reported positive outcomes for both the voice therapy and voice feminization surgery. The benefits of voice therapy, as it is highly satisfactory, mostly increase vocal pitch, and are noninvasive. However, the surgical voice feminization of three-factors modification of vocal folds is also highly competent and provides a maximum absolute increase in vocal pitch. Voice feminization is a long transition journey for physical, neurophysiological, and psychosomatic changes that convert a male phonatory system to a female phonatory system. Therefore, strategies for voice feminization should be individualized according to the individual's physical condition, the desired change in voice pitch, economic conditions, and social roles.
PubMed: 32104050
DOI: 10.2147/IJGM.S205102 -
Advances in Anesthesia Dec 2021With more than 1 million people identifying as transgender in the United States alone, the likelihood of encountering a transgender patient and their family of choice in... (Review)
Review
With more than 1 million people identifying as transgender in the United States alone, the likelihood of encountering a transgender patient and their family of choice in the perioperative setting is very high. A lack of data exists to equitably inform transgender-specific issues, as well as the associated morbidity during the transgender reassignment perioperative period. Anaesthesiologists should actively acquire the knowledge and skills needed to inclusively and respectfully manage these patients and be aware of their unique physiological and psychosocial needs. The pre-operative approach includes a detailed history, focusing on the patients cross-sex hormone treatment (CSHT) regimen and associated medical conditions. An in-depth understanding of commonly used hormones such as estrogen and testosterone and their effect in the perioperative periods is essential. The physical examination should be relevant to the anatomy that is currently present while taking into consideration feminising and masculinising procedures (e.g., genioplasty, thyroid cartilage augmentation), how these interventions alter the anatomy, and potential airway complications. Laboratory results should be interpreted with care – and with expert assistance if needed - as hormone therapy might affect reference values. In addition, risk assessment tools should be used with caution since they often include sex in their scoring system but do not account for the use of CSHT. Intraoperative considerations include urethral catheter placement, drug dosing, and drug interactions that are commonly encountered in the transgender patient. Special attention should be taken in transgender females who have undergone vocal feminization, as case reports have described unexpected difficult airway management. A multimodal approach, which includes regional blocks and attention to pre-existing chronic pain conditions, should be employed as part of the post-operative pain management plan. The post-operative nausea and vomiting risk has not yet been established in this population, requiring appropriate anti-emetic prophylaxis. Despite societal advances that improve transgender health, the medical community still lacks empirical evidence to effectively mitigate the distinctive challenges confronted by this at-risk population.
Topics: Humans; Sex Reassignment Surgery; Transgender Persons
PubMed: 34715982
DOI: 10.1016/j.aan.2021.07.005 -
Translational Andrology and Urology Dec 2016Many transgender men and women seek hormone therapy as part of the transition process. Exogenous testosterone is used in transgender men to induce virilization and... (Review)
Review
Many transgender men and women seek hormone therapy as part of the transition process. Exogenous testosterone is used in transgender men to induce virilization and suppress feminizing characteristics. In transgender women, exogenous estrogen is used to help feminize patients, and anti-androgens are used as adjuncts to help suppress masculinizing features. Guidelines exist to help providers choose appropriate candidates for hormone therapy, and act as a framework for choosing treatment regimens and managing surveillance in these patients. Cross-sex hormone therapy has been shown to have positive physical and psychological effects on the transitioning individual and is considered a mainstay treatment for many patients. Bone and cardiovascular health are important considerations in transgender patients on long-term hormones, and care should be taken to monitor certain metabolic indices while patients are on cross-sex hormone therapy.
PubMed: 28078219
DOI: 10.21037/tau.2016.09.04 -
Philosophical Transactions of the Royal... Sep 2017During sex determination, genetic and/or environmental factors determine the cascade of processes of gonad development. Many organisms, therefore, have a developmental... (Review)
Review
During sex determination, genetic and/or environmental factors determine the cascade of processes of gonad development. Many organisms, therefore, have a developmental window in which their sex determination can be sensitive to, for example, unusual temperatures or chemical pollutants. Disturbed environments can distort population sex ratios and may even cause sex reversal in species with genetic sex determination. The resulting genotype-phenotype mismatches can have long-lasting effects on population demography and genetics. I review the theoretical and empirical work in this context and explore in a simple population model the role of the fitness of chromosomally aberrant YY genotypes that are a consequence of environmentally induced feminization. Low is mostly beneficial for population growth. During feminization, low reduces the proportion of genetic males and hence accelerates population growth, especially at low rates of feminization and at high fitness costs of the feminization itself (i.e. when feminization would otherwise not affect population dynamics much). When sex reversal ceases, low mitigates the negative effects of feminization and can even prevent population extinction. Little is known about in natural populations. The available models now need to be parametrized in order to better predict the long-term consequences of disturbed sex determination.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.
Topics: Animals; Female; Genotype; Male; Models, Genetic; Population Dynamics; Population Growth; Sex Determination Processes; Sex Ratio
PubMed: 28760767
DOI: 10.1098/rstb.2016.0326 -
Cell Host & Microbe Jun 2021The most widespread intracellular bacteria in the animal kingdom are maternally inherited endosymbionts of the genus Wolbachia. Their prevalence in arthropods and... (Review)
Review
The most widespread intracellular bacteria in the animal kingdom are maternally inherited endosymbionts of the genus Wolbachia. Their prevalence in arthropods and nematodes worldwide and stunning arsenal of parasitic and mutualistic adaptations make these bacteria a biological archetype for basic studies of symbiosis and applied outcomes for curbing human and agricultural diseases. Here, we conduct a summative, centennial analysis of living in the Wolbachia world. We synthesize literature on Wolbachia's host range, phylogenetic diversity, genomics, cell biology, and applications to filarial, arboviral, and agricultural diseases. We also review the mobilome of Wolbachia including phage WO and its essentiality to hallmark reproductive phenotypes in arthropods. Finally, the Wolbachia system is an exemplar for discovery-based science education using biodiversity, biotechnology, and bioinformatics lessons. As we approach a century of Wolbachia research, the interdisciplinary science of this symbiosis stands as a model for consolidating and teaching the integrative rules of endosymbiotic life.
Topics: Animals; Bacteriophages; Biological Evolution; Feminization; Host Microbial Interactions; Host Specificity; Humans; Male; Phenotype; Phylogeny; Preventive Medicine; Symbiosis; Wolbachia
PubMed: 33945798
DOI: 10.1016/j.chom.2021.03.006 -
Seminars in Plastic Surgery Aug 2022The use of virtual surgical planning (VSP) and three-dimensional printing (3DP) technologies in the routine facial feminization surgery practice has gained a significant... (Review)
Review
The use of virtual surgical planning (VSP) and three-dimensional printing (3DP) technologies in the routine facial feminization surgery practice has gained a significant popularity over the past few years. The clinical applications of them are claimed to improve safety, accuracy, and efficiency of facial feminization surgeries. In this article, we review and discuss the current applications of VSP and 3DP in different facial feminization procedures.
PubMed: 36506273
DOI: 10.1055/s-0042-1754388 -
Sexual Development : Genetics,... 2016Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while... (Review)
Review
Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexual differentiation aligns with that expounded for other vertebrates; upon sexual differentiation, the gonads secrete sex steroid hormones that masculinise or feminise the rest of the body. However, recent studies on naturally occurring or experimentally induced avian sex reversal suggest a significant role for direct genetic factors, in addition to sex hormones, in regulating sexual differentiation of the soma in birds. This review will provide an overview of sex determination in birds and both naturally and experimentally induced sex reversal, with emphasis on the key role of oestrogen. We then consider how recent studies on sex reversal and gynandromorphic birds (half male:half female) are shaping our understanding of sexual differentiation in avians and in vertebrates more broadly. Current evidence shows that sexual differentiation in birds is a mix of direct genetic and hormonal mechanisms. Perturbation of either of these components may lead to sex reversal.
Topics: Animals; Birds; Disorders of Sex Development; Female; Gonads; Male; Ovary; Sex Determination Processes; Sex Differentiation; Testis
PubMed: 27529790
DOI: 10.1159/000448365 -
German Medical Science : GMS E-journal 2014Phytoestrogens are present in certain edible plants being most abundant in soy; they are structurally and functionally analogous to the estrogens. Phytoestrogens have... (Review)
Review
Phytoestrogens are present in certain edible plants being most abundant in soy; they are structurally and functionally analogous to the estrogens. Phytoestrogens have been applied for compensation of hormone deficiency in the menopause. At the same time, soy products are used in infant food and other foodstuffs. Furthermore, soy is applied as animal fodder, so that residual phytoestrogens and their active metabolites such as equol can remain in meat and influence the hormonal balance of the consumers. There have been only singular reports on modified gender-related behavior or feminization in humans in consequence of soy consumption. In animals, the intake of phytoestrogens was reported to impact fertility, sexual development and behavior. Feminizing effects in humans can be subtle and identifiable only statistically in large populations.
Topics: Animal Feed; Animals; Female; Feminization; Fertility; Humans; Male; Phytoestrogens; Sexual Development; Soy Foods
PubMed: 25587246
DOI: 10.3205/000203