The Science of Sexual Development
Apr 05, 21 | 01:38:22
In this episode, I discuss how hormones such as testosterone and estrogen and their derivatives impact the early development of the brain and body and their maturation. I review published data on environmental factors shown to powerfully alter hormone pathways in animals and humans and the effects of cannabis, alcohol and cell phones on testes, sperm, ovaries and hormones. I describe the predictable relationship between genes, beard growth and balding patterns, and the importance of estrogen for brain development in people of all chromosomal sexes. Finally, I discuss how the hormones we are exposed to in the womb shape the relative length of our finger digits, the sounds our ears make (yes you read that correctly), and how those correlate with people's self-reports of their sexual preferences. As always, basic information and tools are discussed.
Read the full show notes for this episode at hubermanlab.com.
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Timestamps
00:00:00 Introduction
00:00:30 AG1, LMNT & Waking Up
00:06:47 Announcement: Mood Meter App Works Again
00:08:00 Maximizing Learning from the Podcast
00:10:00 New Non-Sleep Deep Rest Protocol, Spanish Subtitles
00:11:35 Sexual Differentiation: Hormones, Neurons & Behavior
00:14:15 Hormones Basics
00:15:26 Sperm Meets Egg, Chromosomal Sex, Gonadal Sex
00:17:50 Y Chromosome Inhibition of Feminization
00:19:00 Placenta Is An Endocrine (Hormone-Producing) Organ, Adrenal Testosterone
00:19:45 Hormonal Sex, Morphological Sex
00:21:04 Hormones Fast & Slow, Sex Steroids Can Turn On Genes
00:23:06 Masculinization, Feminization, Demasculinization, Defeminization
00:23:42 Primary Sexual Characteristics: DHT Drives Penis Development
00:27:03 Secondary Sexual Characteristics
00:27:43 Penis Sprouting: Guevedoces
00:31:25 Estrogen, NOT Testosterone, Masculinizes The Brain
00:33:15 Breast Development In Males: Aromatase; Puberty, & Steroids in Athletes
00:34:50 Estrogen Powerfully Controls Brain Development In All Individuals
00:35:19 Avoiding Hormonal Disruption In Children & Adults: Specific Oils, Creams, Etc.
00:39:00 Environmental Endocrine Disruptors, Sperm Count Decline, Vincloziline
00:44:20 Androgen Insensitivity Syndrome: Hormones Need Receptors, SARMS
00:48:41 Estrogen Establishes “Masculine” Brain Circuits, Testosterone
00:49:42 Cannabis, Alcohol: In Babies, Puberty & Adults
00:56:25 Cell Phone Technology: Effects On Hormones, Ovaries, & Testicles
01:02:33 Beards & Baldness Patterns Around the World, DHT, 5-alpha-reductase
01:06:39 Creatine & DHT/Hair Loss
01:08:20 Predicting Aging Rates By Pubertal Rates
01:10:04 Hyenas, Baseball, & Jumbo Clitorises: Androstenedione
01:14:26 Intersex Moles
01:15:40 Marijuana Plants, Pollens: Plant-To-Animal “Warfare”
01:20:08 Finger Length Ratios, Prenatal Hormone Exposure & Sexual Orientation
01:29:13 Brain Dimorphisms with Sexual Orientation
01:32:00 “Older Brother Effects”: Male Fetuses Might Change Mothers & Subsequent Brothers
01:35:06 The Path Forward & A Warning
01:35:55 Support & Your Questions