Parents have increasingly pressured doctors to delay vaccines for young children, making their kids and others vulnerable to preventable diseases, a study suggests. The findings are in a national survey of pediatricians and family doctors asked about parents wanting to postpone some of the many shots recommended for children younger than age 2. Nearly all doctors said that at least some parents had requested vaccine delays in a typical month; and 1 in 4 said those numbers had increased since the previous year.