"Inside Edition" Thursday said DNA results indicate an 88.7 percent probability that Suzan is related to singer Gary, the oldest son of Jerry Lewis.
Suzan has tried to get Jerry Lewis to acknowledge her as his biological daughter for years.
To help her find out, Gary Lewis agreed to a DNA request by "Inside Edition" to test the claims of Suzan, whose late mother claimed she had an affair with the comedy star, which resulted in Suzan's birth in 1952.
Jerry Lewis, who recently received an Oscar for his humanitarian work, has never publicly acknowledged Suzan as his daughter and declined comment for an "Inside Edition" report last month on her paternity claims.
Rick Saphire, personal manager to both Suzan and Gary, told UPI in an e-mail that the DNA lab found Suzan and Gary share an allele, which is only found in 4.1 percent of the Caucasian population.
"The probability of two unrelated Caucasians is less than 1-10th of 1 percent," Saphire said. "The combined scientific, physical, statistical, and testimonial evidence puts all doubts to rest: Gary Lewis and Suzan Lewis are half brother and sister, and Jerry Lewis is their biological father."