In Brief:

Combined date from 2002 to 2007 indicate that over 8.3 million children under 18 years of age (11.9 percent) lived with at least one parent who was dependent on or abused alcohol or an illicit drug during the past year.

Of these, almost 7.3 million (10.3 percent) lived with a parent who was dependent on or abused alcohol, and about 2.1 million (3.0 percent) lived with a parent who was dependent on or abused illicit drugs.

About 5.4 million children under 18 years of age lived with a father who met the criteria for past year substance dependence or abuse, and 3.4 million lived with a mother who met the criteria.

Source: The NSDUH Report (Substance Abuse and Mental Health Services Administration)

http://oas.samhsa.gov/2k9/SAparents/SAparents.pdf