Dra. Belén Lledó

Can I choose the sex of my embryos when I undergo embryo transfer?

The human genome consists of 46 chromosomes: 23 of these are inherited from our father and the other 23 are inherited from our mother. Our organism’s entire genetic make-up is stored in these chromosomes. The 23 pairs are organised as follows: 22 pairs, known as autosomes, and one pair of sex chromosomes (X and Y) which differentiate the two sexes (XY for males and XX for females).
From a technical point of view, using pre-implantation genetic diagnosis, we have the means of analysing an embryo’s entire chromosomal make-up. This technique, which is known as PGS/PGT-A/CCS (Comprehensive Chromosome Screening), means additional or a lack of any chromosomes in the embryo can be detected. Therefore, we can use PGS/PGT-A/CCS to analyse the entire make-up of the embryo and determine that there are neither DNA excesses nor deficiencies which will stop the embryo from developing properly. But, if we focus on the sex chromosomes, we can also determine if the analysed embryo has two X chromosomes and will, therefore, be a girl (XX) or one X chromosome and one Y chromosome (XY) and will be a boy. […]

2018-03-26T19:17:10+02:0029 de July de 2016|0 Comments

Difference between identical and fraternal twins

Before establishing the biological origin differences between identical and fraternal twins, let’s make a quick note on the etymology of both words.
Etymologically both terms have the same origin (Latin gemellicium) and were used interchangeably to refer to children born in the same delivery. The only difference was the use of the term fraternal twin in the popular speech twin and identical twin in the cultivated speech. However, the semantic evolution of both words has been accompanied by the numerous advances in the field of genetics and knowledge of the development of the human embryo. In fact, since they differ in the latest edition of the dictionary of the RAE: […]

2014-04-17T14:08:43+02:0017 de April de 2014|0 Comments
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