The negative impact that powdered milk substitutes for babies can have on their health is now widely appreciated in the first world. Until about 1980, in many first-world countries, there had been a steady decline in breastfeeding as more and more mothers opted for bottle feeding. The arguments for it seemed persuasive – it allowed partners to share in the chore, especially at night, mothers could return to work or other activities during the day, it allowed mothers to maintain a better bosom shape and so forth. However, the weight of medical and scientific evidence began to move in the other direction as research established that breast-fed babies bonded better with their mothers and that breast milk carried certain immunological protections and nutritional values which powdered milk could not. Breastfeeding was also shown to be of great psychological and physiological benefit to the mother and allowed her endocrine balance to be restored better after the birth. For the past 20 years or so, the situation has begun to change, with an increase in breastfeeding in the first world.