To protect vulnerable 16 and 17 year olds, the offences of 'abuse of a position of trust' prohibits sexual contact between adults and children under 18 in schools, colleges and residential care.
Chromosome abnormalities usually happen as a result of an error in cell division. Meiosis is the name used to describe the cell division that the egg and sperm undergo when they are developing. Normally, meiosis causes a halving of chromosome material, so that each parent gives 23 chromosomes to a pregnancy.
In cases in which only a percentage of cells contains the trisomy 13 abnormality (mosaicism), errors may also occur during cellular division after fertilization (mitosis). In about 20 percent of affected individuals, trisomy 13 results from a translocation involving chromosome 13 and another chromosome.