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.
Nuclear divisions occur in both mitosis and meiosis. In mitosis, the result is the division of duplicated copies of genome into two. In meiosis, nuclear division occurs twice, dividing the originally single nucleus into four nuclei that are genetically different from one another.