A human female is born with all the egg cells she will ever have. The possibility for the development of new oocytes is zero. Given this constraint, it is crucial that these gametes remain healthy and ...

The brain is shielded from many substances by the blood-brain barrier, but this shield is not impenetrable. There are immune cells in the brain called microglia that can respond to potential invaders ...

During pregnancy, maternal and fetal cells migrate back and forth across the placenta, with fetal cells entering the mother's ...

Scientists have uncovered a direct molecular mechanism by which gut bacteria inject proteins into human cells, reshaping immune responses and potentially driving inflammatory disease. Scientists have ...

Researchers are learning how to refill the energy reserves of aging human cells, turning a long-standing metaphor about “cellular batteries” into a literal engineering challenge. By training healthy ...

Scientists have created human eggs containing genes from adult skin cells, a step that someday could help women who are infertile or gay couples have babies with their own genes but would also raise ...