Before you say 'put up or shut up' Mr Gray, this is one such study, not of children but adults.
http://www.ncbi.nlm.nih.gov/pubmed/8332896
Science. 1993 Jul 16;261(5119):321-7.
A linkage between DNA markers on the X chromosome and male sexual orientation.
Hamer DH, Hu S, Magnuson VL, Hu N, Pattatucci AM.
Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Comment in:
* Science. 1993 Dec 24;262(5142):2063-5.
* Science. 1993 Sep 3;261(5126):1257; author reply 1259.
* Science. 1993 Jul 16;261(5119):291-2.
* Science. 1993 Sep 3;261(5126):1258-9.
Abstract
The role of genetics in male sexual orientation was investigated by pedigree and linkage analyses on 114 families of homosexual men. Increased rates of same-sex orientation were found in the maternal uncles and male cousins of these subjects, but not in their fathers or paternal relatives, suggesting the possibility of sex-linked transmission in a portion of the population. DNA linkage analysis of a selected group of 40 families in which there were two gay brothers and no indication of nonmaternal transmission revealed a correlation between homosexual orientation and the inheritance of polymorphic markers on the X chromosome in approximately 64 percent of the sib-pairs tested. The linkage to markers on Xq28, the subtelomeric region of the long arm of the sex chromosome, had a multipoint lod score of 4.0 (P = 10(-5), indicating a statistical confidence level of more than 99 percent that at least one subtype of male sexual orientation is genetically influenced.
PMID: 8332896 [PubMed - indexed for MEDLINE]