The Environmental Protection Agency (EPA) established a rule in 2008 that demands anyone doing renovation work on residential buildings constructed before 1978 to take precise steps to reduce the particles generated when the paint is disturbed. The reason behind this ruling is because it may contain lead from lead-based paint. The LRRP Rule requires any renovation work — and all door and window replacements — that disturbs more than six square feet of a pre-1978 home’s interior to comply with meticulous and costly work practices to protect residents from exposure to lead, it can be exceptionally dangerous to children.
The lead paint can be very harmful to their cognitive growth in particular.
Windows are considered a higher lead exposure risk than other housing components because of weathering and the effect of friction on paint.
PS: If your home is built before 1978 maybe it's time to consider changing them, better to be safe than sorry.