In order to prove the identity of the people involved through a legally valid test, they must provide the following documents:

1. A publicly recognised valid ID document (national ID card, passport, alien’s residence card).
2. Recent photograph in the case of minors.
3. Authorisation of the minor’s legal guardian to take the sample, which is to be document by means of a family record book or birth certificate (in the case of minors).

In addition, the laboratory which takes the samples (collaborating centre or Citogen) must fill out an APPLICATION that collects all the data about the participants. This application consists of:

• Informed consent where the characteristics of these tests are explained. The person(s) requesting the test much grant their authorisation to these tests being carried out by signing it.
• Family members’ data and pathological history of interest that may influence the test results’ assessment (recent blood transfusions, transplants, etc.).
• Delivery of reports. It is essential to indicate and sign the box which specifies to whom the report is to be sent.
• Information on the Centre and payment method.
• Custody chain: Identification and signature of the person who takes the samples and data related thereof.

Human DNA is not the same in all people. There are variable or polymorphic zones that allow individuals to be differentiated and biologically identified. Each human being therefore has a unique “genetic profile” or “genetic fingerprint”, with the exception of monozygotic twins whose genetic profile is identical.

In Forensic Genetics, the variable DNA regions most commonly used to carry out these studies are the so-called STR (Short Tandem Repeats), which are very frequent and are located along the entire genome.

These tests are based on comparing the genetic profile of the two people involved in the test (for instance, son/daughter and their presumed father) to subsequently carry out a statistical analysis that reveals the likelihood of kinship.

The most frequent cases in which a maternity test is usually requested are the following:

• To confirm an adopted child’s biological mother
• To prove kinship to Civil Registries for the purpose of reunifying immigrant families
• To confirm that an embryo conceived through in-vitro fertilisation was implanted into the correct mother’s womb
• To resolve situations where the mother or hospital staff suspect that there has been a mix-up of babies in the baby unit

Yes, it is possible to conduct studies on other kinship relationships, such as: sibling, grandfather/grandmother-grandchildren, uncle/aunt-nephew/niece relationships, etc. These kind of tests are very useful in cases where paternity/maternity needs to be determined and the DNA of the alleged parent is not available because he or she has died or is missing.

Paternal lineage studies (Y chromosome)

Studying Y chromosome’s genetic profile is highly useful to establish or rule out paternal lineage relationships between individuals because said chromosome is transmitted from fathers to sons. Thus, two male individuals who have an identical Y chromosomes have an ascending male kindship relationship. In the contrary, if their Y chromosomes are different, this kind of relationship can be ruled out.

Maternal lineage studies (mitochondrial DNA)

In the case of mitochondrial DNA, it is only transmitted by mothers to their children, but cannot be transmitted by fathers. Studying the genetic profile of mitochondrial DNA can therefore be used to establish or rule out maternal lineage relationships. In cases where it is suspected that two people may be related through the maternal line, it can be concluded that this kind of relationship exists if the mitochondrial DNA of both is identical. On the contrary, such a relationship can be ruled out if it is different.

Yes, this is a prenatal paternity test. If you wish to verify the future baby’s prenatal paternity and their alleged father during pregnancy, there are two options:

Amniotic fluid prenatal paternity test (invasive)

The test is conducted using an amniotic fluid or chorionic villus sample obtained by a gynaecologist in the weeks set forth for this kind of procedures. A blood sample of the presumed father and a sample of the mother’s blood are likewise necessary.

Maternal blood paternity test (non-invasive)

The test requires a simple analysis of the mother’s blood. During the pregnancy, foetal DNA circulates through the mother’s blood, which can be extracted and analysed for genetic profiling in order to compare it with that of the presumed father. The sample can be taken as from the 8th week of gestation and it also allows the baby’s sex to be known.

Yes, this is a prenatal paternity test. If you wish to verify the future baby’s father-child relationship and their presumed father during pregnancy, there are two options:

Amniotic fluid paternity test (invasive)

The test is conducted using an amniotic fluid or chorionic villus sample that has been obtained by a gynaecologist in the weeks set forth for this kind of procedures. A blood sample of the presumed father and a sample of the mother’s blood are likewise necessary.

Maternal blood paternity test (non-invasive)

The test requires a simple analysis of the mother’s blood. During the pregnancy, foetal DNA circulates through the mother’s blood, which can be extracted and analysed for genetic profiling in order to compare it with that of the presumed father. The sample can be taken as from the 8th week of gestation and it also allows the baby’s sex to be known.