and methods were added, including antibodies, from 1987 through 1997. At the time of the patent filing, both Lawrence Livermore National Laboratories and the USDA were only sorting fixed sperm nuclei, after the Application Serial Number 35,986 patent filing a new technique was utilized by the USDA where "sperm were briefly sonicated to remove tails". USDA in conjunction with Lawrence Livermore National Laboratories, 'Beltsfield Sperm Sexing Technology' relies on the DNA difference between the X- and Y- chromosomes. Prior to flow cytometric sorting, semen is labeled with a fluorescent dye called Hoechst 33342 which binds to the DNA of each spermatozoon. As the X chromosome is larger (i.e. has more DNA) than the Y chromosome, the "female" (X-chromosome bearing) spermatozoa will absorb a greater amount of dye than its male (Y-chromosome bearing) counterpart. As a consequence, when exposed to UV light during flow cytometry, X spermatozoa fluoresce brighter than Y- spermatozoa. As the spermatozoa pass through the flow cytometer in single file, each spermatozoon is encased by a single droplet of fluid and assigned an electric charge corresponding to its chromosome status (e.g. X-positive charge, Y-negative charge). The stream of X- and Y- droplets is then separated by means of electrostatic deflection and collected into separate collection tubes for subsequent processing. In 1994, the first British baby was born through gender selection Sophie-May Clark. Recently, a study published in 2006 indicated that mothers with toxoplasmosis have a significantly higher sex ratio of boys to girls. This has been discussed in connection with the manipulation hypothesis of parasites. Another study found a link between sex and the diet of the mother, but this may be due to statistical chance, and has yet to be confirmed. Legality Sex selection is illegal in most of the world. There is fertility tourism from the United Kingdom, Australia and Canada to the United States for sex selection, because preimplantation genetic diagnosis (PGD, a potential expansion of IVF), which can be used for sex selection, is prohibited in the UK, Australia and Canada, except when it is used to screen for genetic diseases, while the laws in the US are more relaxed in this subject. Sex selection is illegal in China, but the Chinese government admits that the practice is widespread, especially in rural areas of China and among lawless groups such as ghettoized migrant workers in cities. Sex selection is illegal in India. Prenatal determination