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. Thank you to our sponsors AG1: https://athleticgreens.com/huberman LMNT: https://drinklmnt.com/hubermanlab Waking Up: https://www.wakingup.com/huberman 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   Disclaimer & Disclosures