Hi Dear, Understanding Your concern. As per your query you have symptoms of metallic taste in the mouth along with your metallic smell in diapers in child which seems to be due to different issues as chances of your wife seems to have dysgeusia which is caused by changes in your hormone levels during pregnancy. Only possible common cause is poor oral hygiene and medications rich in heavy metals. Need not to worry about it. Visit general physician once and get it examined and start treatment as per diagnosis. Go for citrus food to stimulate your taste buds. Drink plenty of water and take diet rich in multivitamins. Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari