Paternity and maternity studies
Results with up to 99.999999% reliability
The generation of genetic profiles from biological samples (cells, saliva, hair samples with follicle, blood, etc.) allows for the extraction, analysis, and comparison of the DNA profiles of the individuals involved in the study, to determine whether there is a paternity and/or maternity relationship between them.
This is possible because we all inherit genetic material from our parents. Half of our DNA comes from our father, and the other half from our mother.
Once the DNA is extracted from the samples received in our laboratory and the genetic profile is obtained, we conduct a comparative study that allows us to confirm or rule out whether there is a paternal/maternal-filial relationship between the individuals in the study.
How do I initiate a paternity or maternity study process?
No formal request from a judge or lawyer is needed to initiate a paternity or maternity study. Any adult – father, mother, or offspring – can start a genetic study process to confirm whether there is a paternal/maternal-filial relationship with another person.
The steps to follow are:
1
Purchase a Paternity/Maternity Kit
The purchase of the kit can be made directly on our website.
During the purchase process, two options will be offered:
- Buy a kit for an informative paternity/maternity study, the results of which allow certification of the paternal/maternal-filial relationship of the individuals from whom the samples are obtained. The result will not have the status of evidence for a possible legal process. You can perform the sample collection yourself.
- Purchase a study with legal validity, the results of which will have the status of evidence in a possible legal process or before an official body, as all participants in the test must identify themselves with a valid identification document (ID card, passport, etc.). In this case, the sample collection will be carried out in a centre collaborating with Citogen, which will guarantee the chain of custody of the samples throughout the process.
The reliability level of the results in both cases is exactly the same: up to 99.999999%
2
Perform the Sample Collection
If you wish to carry out an informative study to resolve doubts about your relationship with another person, the sample collection can be carried out in the comfort of your home in a very simple way, following the instructions in the kit. During the purchase process, you will be asked to indicate the type of sample you want to provide, such as buccal swab or buccal mucosa cells, blood, or others, as well as an address to receive the sample collection kit. This kit will be sent in an anonymous and discreet package, allowing you to directly manage the collection and preservation of samples from the individuals whose DNA you wish to analyze.
However, if you want the study results to have legal validity in case of a possible judicial process, the sample collection must be carried out in a collaborating laboratory. Before taking the samples, it will be necessary to identify all participating individuals to ensure the validity, origin, and chain of custody of the samples throughout the process. Once the purchase process is completed on our website, we will contact you to provide the address of the laboratory nearest to your postal code and agree on a date when all involved individuals must attend to perform the sample collection. In the case of minors, they must be accompanied by their legal guardian.
3
Sending the Samples to Our Laboratory
All kits sent to homes include a box and a prepaid envelope in which to enclose the samples for mailing via conventional post.
In the case of studies with legal validity, our collaborating laboratory will forward the samples to our laboratory, complying with the chain of custody criteria.
4
Creation of the Genetic Profiles from the Samples
Once the samples are received in our laboratory, they will be anonymized using a unique code and the genetic profile will be obtained.
The analysis will determine, with up to 99.999999% reliability, the paternity/maternity relationship between the individuals participating in the study.
5
Drafting and Sending of the Conclusions Report
Once the analysis is complete, we will issue a results report with the conclusions of the study. In the case of informative tests, the report will be sent in electronic format via email to the address indicated during the purchase process. Click here to see the form you will receive.
The reports of tests with legal validity will also be sent via email to the address indicated in the purchase process. The format will be this.
The estimated time from the receipt of the samples in the laboratory to the sending of the report is 5 working days.
Why trust Citogen for your paternity and maternity studies?
The most reliable answer to many of the questions that keep us awake at night lies in our genes, and at Citogen, we have been specialists in DNA processing, extraction, and analysis since 1998. With over 1000 paternity tests conducted annually and numerous cases resolved in court every year, we have a strong track record.
We are pioneers in clinical and forensic genetics in Spain, widely recognized internationally, and we have the most advanced and modern technologies and facilities in the market, so that anyone can benefit from all the advances achieved in these years in the fields of genetics, genomics, and transcriptomics, at very affordable prices.
Our laboratory complies with the National Commission for the Forensic Use of DNA (CNUFADN) Agreement under the Spanish Ministry of Justice. Additionally, we hold UNE-EN ISO/IEC 17025 accreditation and are members of the International Society for Forensic Genetics (ISFG).



Frequently asked questions
- What is the difference between an informative (anonymous) paternity/maternity test and a legally valid one?
In the case of informative or anonymous tests, there is no need for the identification of the participants, and any type of sample can be used to obtain DNA. Since it is not necessary for samples to be collected by professionals in a laboratory, they can be taken and sent from the privacy of your home in a quick and easy manner. The result of this test is just as conclusive as a legally valid test, but it is purely for informational purposes because we do not have certainty about the identity of the individuals providing the samples.
However, for a paternity/maternity test to have legal validity, it is essential that the samples are collected by professionals who can verify the identities of the participants in the test. Therefore, sample collection can only be done at one of our collaborating centres, after confirming the identity of all individuals involved (in the case of minors, the authorization of their legal guardian is required), to ensure that the samples are indisputable and the chain of custody is guaranteed.
- What type of sample is taken for a paternity/maternity study?
When conducting a paternity/maternity study, the recommended biological sample is a cheek swab. To obtain this sample, a swab, similar to a cotton swab, is used, which is included in the kit. The sample donors should gently rub the inside of each cheek for approximately 25-30 seconds, inside the oral cavity. This way, the necessary cells for genetic analysis are collected.
Additionally, there is the option of taking a blood sample, which is done using a small lancet included in the kit. Through a nearly painless prick on the finger, the required blood sample is obtained, which is then placed on the FTA card provided for further analysis
It is important to note that each method of sample collection has its own characteristics and requirements. If you have any doubts, it is advisable to consult with genetics experts or specialized professionals to choose the most suitable method for each particular case.
- What documentation is required to perform a legally valid paternity/maternity test?
To establish the identity of the individuals involved in a legally valid paternity/maternity test, the following documentation must be provided:
- Valid government-issued photo identification (ID card, passport, residence permit, NIE, etc.).
Recent photograph in the case of minors.
Authorization from the legal guardian of the minor for sample collection, documented through the family book or birth certificate in the case of minors.
In addition, at the laboratory where the sample collection takes place, additional documentation will be provided for completion, including:
- Informed consent, which explains all the characteristics of these tests and must be signed by all participants in the study.
- Request for family data and relevant medical history that may influence the evaluation of analytical results (recent transfusions, transplants, etc.).
- Report delivery address. You can choose to receive the report in electronic format (via email) or in physical format (printed report sent by postal mail). It is essential to specify the recipient’s name and preferred delivery method and sign the request. This information cannot be changed once the sample collection has been performed.
- Valid government-issued photo identification (ID card, passport, residence permit, NIE, etc.).
- I want to take a paternity/maternity test, but I don't want the other person to know. Can I send some other type of sample in the sample envelope included in the kit?
We can perform a paternity/maternity test using a variety of samples (hair with root, saliva in a bottle or cup, nails with some cuticle, blood-soaked gauze, etc.), but in a case like the one you mentioned, it can only be an informational test, without legal validity, as we cannot verify the identity of the sample donor, and we will not be able to identify them in the report. We can determine if there is a parent-child relationship between Sample 1 and Sample 2, but we cannot establish the ownership of the samples.
If the sample collection is not done following the instructions and methodology provided in the kit, it should be noted that the sent sample may not contain DNA.
Each kit includes the necessary components for sample collection from 2 individuals, and you can request additional kits if you need to include samples from more people.
- I have already done a paternity test previously with your laboratory. Do I need to buy a new kit and repeat the process, or can the existing profile be used again?
If a legally valid paternity test was conducted (with sample collection in a laboratory with unequivocal identification of the sample donor using ID card, passport, or legal document with a photograph), and as long as no more than 5 years have passed since the date of the previous test, we can use the previous genetic profile.
In this case, we would only need written authorization from you, as well as samples from the other person. Therefore, you would only need to purchase one kit, and there would be no need to use the second sample collection unit since, in your case, it would not be necessary to collect biological samples for a genetic profile again.
- I have a child through egg donation. Can I confirm whether donor eggs were used or if they are mine?
Absolutely, yes. Through a genetic analysis of a sample from your child and another from you (the mother), we can determine if both share DNA. If the comparison of the genetic profiles of both samples is positive, we would confirm, with up to 99.9998% reliability, that there is a maternal-filial relationship between the two individuals. Conversely, if it gives us a negative result, we could conclude with the same level of reliability that there is no direct maternal-filial relationship between the two individuals, and therefore, your child’s DNA comes from an individual conceived through a fertilization process using a donor egg.
- I have already paid. When will I be given an appointment for sample collection?
Once the purchase of the legally valid study kit is completed, a member of our team will contact you within a maximum of 2 business days to provide you with the address of the nearest collaborating laboratory to your postal code and initiate the process to schedule your appointment.
- How will I receive the report? I want it to be confidential.
We will send the report via email to the address you provide, and we will confirm this with you at the time of sample collection. You will have signed the request form, and we cannot change what you have written and signed.
Our reports are sent in encrypted form so that only the intended recipient of the report can open it with the corresponding password.
- Will I understand the report?
The report you will receive has two clearly differentiated parts.
On the one hand, you will find an explanation of the scientific procedure we have carried out for sample processing, DNA extraction, profiling, and genetic material analysis, as well as for the comparison of the profiles of all samples involved in the study.
On the other hand, there is a text with the study’s result, along with a clear and understandable conclusion.
You can see an example of the final report here:
- View informative paternity/maternity study report.
- View legally valid paternity/maternity study report.
If you have any questions or doubts about the interpretation of the report once you receive it, our team will provide you with the clarifications you need.
- What is chain of custody?
It is a legal term that means we ensure and commit to the fact that the person from whom the sample is taken is who they claim to be, and that their sample will not be changed or altered at any point in the process, from extraction to shipping and subsequent analysis.
It is a necessary requirement to include the identity of the sample donor in the final report of conclusions, making it legally valid and usable in a legal proceeding.
- Is it necessary for the mother to participate in a paternity test?
No. The father can come with the child alone, but he will need to prove that he is the legal guardian of the child by providing the family book or the birth certificate.
- I won't be able to bring the other person to have the sample taken.
In that case, the genetic study can be conducted, but it will only be an informational paternity/maternity test, as it is not possible to confirm with unequivocal certainty the identity of the sample donors.
The result will be just as conclusive, with up to 99.999999% reliability, but the report will not include the names of the sample holders, nor will it have legal validity for potential legal proceedings.