Methods Sex selection

1 methods

1.1 pre-implantation

1.1.1 ericsson method
1.1.2 ivf/pgd technique
1.1.3 timing methods
1.1.4 sperm sorting


1.2 post-implantation
1.3 post-birth

methods
pre-implantation

two major types of pre-implantation methods can used social sex selection. both of them based on actively rendering second sex chromosome either y chromosome (resulting in male), or x chromosome (resulting in female).

the ericsson method

the ericsson method, first applied in clinical setting in 1970s dr. ronald j. ericsson, uses higher concentrations of sperm of desired sex increase likelihood of conceiving sex. method has 70-72% success rate boys , 69-75% success rate girls. currently, approximately 50 gender selection centers in united states use ericsson method artificial gender selection.

the ericsson method separates male , female sperm passing them through column filled blood protein, human serum albumin. sperm enter human serum albumin, differences in mass between x , y chromosomes manifest lighter male sperm push deeper protein females dragged down weight of leg of x sex chromosome. tiny difference creates separate layers of concentrated male , female sperm. layers of gender-selected sperm of higher concentrations not pure. lack of purity explains 30% chance of gender selection failure of ericsson method.

ivf/pgd technique

an 8-celled embryo prior ivf/pgd analysis

after ovarian stimulation, multiple eggs removed mother. eggs fertilized in laboratory using father s sperm in technique called in vitro fertilization (ivf). in vitro latin within glass . fertilized eggs called embryos. embryos develop through mitosis, separated sex. embryos of desired gender implanted in mother s uterus.

prior fertilization ivf, fertilized eggs can genetically biopsied preimplantation genetic diagnosis (pgd) increase fertilization success. once embryo grows 6-8 cell size, small laser incision in egg membrane (zona pellucida) allows safe removal of 1 of cells. every cell in embryo contains identical copy of genome of entire person. removal of 1 of these cells not harm developing embryo. geneticist studies chromosomes in extracted cells genetic defects , definite analysis of embryo’s gender. embryos of desired sex , acceptable genetics placed mother.

the ivf/pgd technique favored on ericsson method because of stricter control of offspring gender in laboratory. since embryos of desired sex transferred mother, ivf/pgd avoids small likelihood present in ericsson method of undesired sperm fertilizing egg. gender selection success rates ivf/pgd high. technique recommended couples not accept child of undesired gender.

timing methods

timing methods aim affect sex ratio of resultant children having sexual intercourse @ specific times related ovulation. studies have not been consistent whether timing methods have influence on sex of baby, showing no correlation , others showing opposite.

the shettles method, first formally theorized in 1960s landrum b. shettles, proposes sperm containing x (female) chromosome more resilient sperm containing y (male) chromosome. method advocates intercourse 2 4 days prior ovulation. time ovulation occurs, cervix should contain higher concentration of female sperm still capable of fertilization (with of male sperm dead). intercourse close ovulation, on other hand, should increase chances of conceiving boy since concentration of y sperm higher @ height of menstrual cycle.
the whelan method intercourse timing method advocates opposite of shettles method. whelan method suggests intercourse 4 6 days prior ovulation increase likelihood of fertilization male sperm.

sperm sorting

sperm sorting advanced technique sorts sperm in vitro flow cytometry. shines laser @ sperm distinguish x , y chromosomes, , can automatically separate sperm out different samples. during mid 1980s, dr. glenn spaulding first sort viable whole human , animal spermatozoa using flow cytometer, , utilized sorted motile rabbit sperm artificial insemination. subsequently, first patent application disclosing method sort 2 viable subpopulations enriched x- or y- sperm filed in april 1987 application serial number 35,986 , later became part of patent 5,021,244; , patent included discovery of haploid expression (sex-associated membrane proteins, or sam proteins) , development of monoclonal antibodies proteins. additional applications , methods added, including antibodies, 1987 through 1997. @ time of patent filing, both lawrence livermore national laboratories , usda sorting fixed sperm nuclei, after application serial number 35,986 patent filing new technique utilized usda sperm briefly sonicated remove tails . usda in conjunction lawrence livermore national laboratories, beltsfield sperm sexing technology relies on dna difference between x- , y- chromosomes. prior flow cytometric sorting, semen labeled fluorescent dye called hoechst 33342 binds dna of each spermatozoon. x chromosome larger (i.e. has more dna) y chromosome, female (x-chromosome bearing) spermatozoa absorb greater amount of dye male (y-chromosome bearing) counterpart. consequence, when exposed uv light during flow cytometry, x spermatozoa fluoresce brighter y- spermatozoa. spermatozoa pass through flow cytometer in single file, each spermatozoon encased single droplet of fluid , assigned electric charge corresponding chromosome status (e.g. x-positive charge, y-negative charge). stream of x- , y- droplets separated means of electrostatic deflection , collected separate collection tubes subsequent processing. technology in commercial use animal farming. being trialed on humans in under trademark microsort; claims 90% success rate still considered experimental fda.

post-implantation

sex selection after implantation can performed prenatal sex discernment, followed sex-selective abortion of offspring of unwanted sex. prenatal sex discernment, blood test can taken mother testing of small amounts of fetal dna within it, , has been estimated reliable more 98% of time, long samples taken after seventh week of pregnancy.

post-birth

sex-selective infanticide - killing children of unwanted sex. though illegal in parts of world, still practiced.

sex-selective child abandonment - abandoning children of unwanted sex. though illegal in parts of world, still practiced.

sex-selective adoption - placing children of unwanted sex adoption. less commonly viewed method of social sex selection, adoption affords families have gender preference legal means of choosing offspring of particular sex.