Sibling relationships shape us in complex ways: therapist Jürg Frick highlights gender, age gaps and upbringing as key influences; Alfred Adler’s early theories on birth order are challenged by Julia Rohrer’s data showing little impact, though women with younger brothers tend to earn less. Medical advances raise ethical questions with “savior siblings” like Jamie Whitaker, born to save his brother’s life. Meanwhile, twin studies continue to probe whether genetics or environment drive conditions such as obesity, heart disease and Long COVID.
