I am now referring to specific studies, and therefore will cite my sources.
Investigations That Present Empirical Data on ASL/English Bilingual Methodology
Andrews, Ferguson, Roberts, & Hodges (1997) N=7
Results: Bilingual-bicultural program had a significant positive impact on students in pre-kindergarten through 1st grade in a number of areas, including basic concepts, auditory comprehension, picture vocabulary, English grammar, reading, ASL competency, English writing tasks, and mathematics.
Hoffmeister (2000). N=78
Results: A relationship between ASL knowledge and specific reading skills was observed. Students with extensive ASL exposure scored better on ASL and reading comprehension tasks than those with limited exposure to ASL. ASL users also outperformed users of Manually Coded English on MCE tasks.
Kuntze (2004). N=91
Results: Levels of ASL passage comprehension had a significant predictive power regarding English passage comprehension. Significant differences were shown between the ASL and English literacy skills of deaf children of deaf parents and the skills of deaf children of hearing parents.
Li (2005). N=15
Results: Student spelling scores and understanding of science concepts significantly increased with the use of preview—view-review, a blilingual technique. Deaf bilingual students experienced statistically significant gains compared to hearing bilingual students.
Mayberry (1989, 1999) Mayberry, & Chamberlain, Waters & Doehring (1999). N=48
Results: Statistically significant relationships were found between ASL and English story comprehension measures and SAT-9 Reading subtest scores.
Moores, et.al. (1987); Moores & Sweet (1990). N=130
Results: Non-significant relationships were found between ASL language proficiency interviews and a composite of 5 standardized reading measures for students aged 16-18.
Nover, Andrews, Baker, Everhart, & Bradford (2002). N=122
Results: It was found that students with ASL/English bilingually trained teachers had significantly improved SAT-9 English Vocabulary and Language subtest scores. Younger students (aged 8-12 years) scored significantly higher than the national norms on the SAT-9 English Vocabulary, Reading, and Language subtests. Parental hearing status influenced performance only for older students.
Padden & Ramsey (1998). N=31
Results: It was found that ASL test results correlated with reading comprehension, regardless of parental hearing status. A relationship was discovered between ASL sentence order, ASL verb agreement, ASL sentence imitation, fingerspelling, and initialized signs.
Prinz (1998); Prinz & Strong (1998); Strong & Prinz (1997). N=155
Results: Statistically significant correlations between ASL proficiency and English literacy were found. Researchers observed that students with deaf mothers outperformed students with hearing mother only on ASL and English tasks when the hearing mothers had low ASL ability.
Singleton, Supalla, Litchfield, and Schley (1998). N=80
Results: It was found exposure to ASL enhances ASL ability. After age 9 years, highly ASL- fluent deaf children of hearing parents were outperforming less ASL-fluent peers on several English writing tasks.
Smith (2006). N=123
Results: Students with higher Reading Comprehension scores on the SAT-9 also scored better on ASL phonology, morphology, syntax, and pragmatic tasks on the Test of ASL-Revised. This relationship was statistically significant.
Delana, Gentry, & Andrews (2007). The efficacy of ASL/English bilingual education: Considering public schools. American Annals of the Deaf. 152(1). p 73-87
This is but a small sample of the research available.
Now, for those doubters, please provide your support of your claims. Quite obviously, my statement regarding the availability on numerous studies was true, despite your attempts to discredit said statement.