To what extent sexual orientation is due to one’s environment and one’s biology is still a matter of controversy, but it has been well established that there is a biological component [1] evident in the coincidence of various biological traits with one’s orientation, including blood typing, rhesus factor [2], relative size of digital segments [3], spacing of cutaneous appendages [4], chemotactic preference of body odor [5], and of course high incidence of shared sexual orientation among monozygotic twins [6] (even in cases where said twins were separated at birth [7]). Today’s interest includes determining what effect one’s matrilineal heritability has on one’s sexual orientation [8] (whether that be due to X-linked genes [9], maternal proteins in the egg [10], or pre-natal paracrine and endocrine factors [11]). All of the objects of study in the literature involve obviously biological factors over which nobody has conscious or subconscious control, and unlike your mere anecdotes, these were observed under controlled conditions using properly designed experimentation, and actual statistics to determine if the data is even significant [12].
[1] Jannini, E. A.; Blanchard, R.; Camperio-Ciani, A.; et al. Male Homosexuality: Nature or Culture?
Journal of Sexual Medicine, 7:10, 3245-3253 (2010).
[2] Ellis, L.; Ficek, C.; Burke, D.; et al. Eye color, hair color, blood type, and the rhesus factor: Exploring possible genetic links to sexual orientation.
Archives of Sexual Behavior, 37:1, 145-149 (2008).
[3] Hall, L. Dermatoglyphic Analysis of Total Finger Ridge Count in Female Monozygotic Twins Discordant for Sexual Orientation.
Journal of Sex Research, 37:4, 315-320 (2000).
[4] Kirk, K. M.; Bailey, J. M.; Dunne, M. P.; et al. Measurement Models for Sexual Orientation in a Community Twin Sample.
Queensland Institute of Medical Research, 30:4, 345-356 (2000).
[5] Martins, Y.; Preti, G.; Crabtree, C. R.; et al. Preference for Human Body Odors Is Influenced by Gender and Sexual Orientation.
Psychological Science, 16:9, 694-701 (2005).
[6] Buhrich, N.; Bailey, J. M.; Martin, N. G. Sexual orientation, sexual identity, and sex-dimorphic behaviors in male twins.
Behavior Genetics, 21:1, 75-83 (1991).
[7] Joseph, J. Separated Twins and the Genetics of Personality Differences: A Critique.
American Journal of Psychology, 114:1, 1-30 (2001).
[8] Iemmola, F.; Camperior-Ciani, A. New Evidence of Genetic Factors Influencing Sexual Orientation in Men: Female Fecundity Increase in the Maternal Line.
Archives of Sexual Behavior, 38:3, 393-399 (2009).
[9] Craig, I. W.; Harper, E.; Loat, C. S. The Genetic Basis for Sex Differences in Human Behaviour: Role of the Sex Chromosomes.
Journal of Phycology, 68:3, 269-284 (2004).
[10] DuPree, M. G.; Mustanski, B. S.; Bocklandt, S.; et al. A Candidate Gene Study of CYP19 (Aromatase) and Male Sexual Orientation.
Behavior Genetics, 34:3, 243-250 (2004).
[11] McGuffin, P.; Riley, B.; Plomin, R. Toward Behavioral Genomics.
Science, 291:5507, 1232-1459 (2001).
&
Doerner, G.; Poppe, I.; Stahl, F.; et al. Gene- and environment-dependent neuroendocrine etiogenesis of homosexuality and transsexualism.
Institute of Experimental Endocrinology, 98:2, 141-150 (2001).
[12] Gavrilets, S.; Rice, W. R. Genetic models of homosexuality: generating testable predictions.
Proceedings of the Royal Society London, 273, 3031-3038 (2006).