Detailed answer — steps to prove parentage and secure inheritance (Illinois law)

This section explains practical steps and the legal framework under Illinois law. It assumes you start with no prior legal knowledge.

1. Understand the legal framework

Two Illinois bodies of law are most relevant:

• The Illinois Parentage Act governs how parentage is established (commonly cited as 750 ILCS 45/). See Illinois Courts information on paternity: illinoiscourts.gov/topics/family-law/paternity.
• The Illinois Probate Act governs intestate succession and the process for distributing a decedent’s estate (commonly cited as 755 ILCS 5/). See the Illinois General Assembly statutes index for details: ilga.gov — Illinois Compiled Statutes.

2. Check for a Voluntary Acknowledgment of Paternity (AOP)

When a child is born outside marriage, parents sometimes sign an AOP at the hospital or later with the Vital Records office. If an AOP exists and was properly filed, it is strong evidence of legal paternity. Contact the Illinois Department of Public Health Vital Records to ask whether an AOP exists for your birth: Illinois Vital Records — Birth Certificates.

3. Collect documentary evidence

Gather anything that supports a parent-child relationship. Examples include:

• Letters, emails, text messages, or social media messages between your mother and the decedent referring to parenthood.
• Photographs showing you with the decedent over time.
• Medical records or school records listing the decedent as parent or emergency contact.
• Wills, trusts, insurance beneficiary forms, or other estate documents that refer to you as a child or beneficiary.
• Affidavits (sworn statements) from relatives, friends, or caregivers who can testify about the relationship.

4. Use genetic (DNA) testing when possible

If the alleged father is alive, an agreed DNA test (court-ordered if necessary) will almost always establish paternity. If the alleged father is deceased, you may still be able to obtain DNA through:

• a stored medical sample (if available), or
• DNA from surviving close relatives (e.g., the decedent’s children, siblings, or parents) for kinship testing.

Courts accept properly administered DNA results as powerful evidence. The Parentage Act and Illinois courts permit DNA testing to resolve parentage questions.

5. File the right case in the right court

Your path depends on whether the decedent’s estate is open and whether someone is already administering the estate:

• If an estate is in probate: notify the estate representative (executor/personal representative). You can petition the probate court to be recognized as an heir or to have the court order genetic testing or otherwise adjudicate parentage for inheritance purposes.
• If no estate administration has started: you may file a paternity action under the Illinois Parentage Act (usually in the circuit court in the county where you or the decedent lived). A paternity judgment establishes parentage for all legal purposes, including inheritance.

In probate matters, the court ultimately evaluates the evidence and issues orders about distribution under the Probate Act (see 755 ILCS 5/). If necessary, the court can combine or coordinate paternity and probate actions.

6. Time limits and practical considerations

Time can matter. Some claims—especially challenges to wills or late claims against an estate—have strict deadlines under the Probate Act. If you learn of an estate or a probate filing, act quickly to file a claim or petition to protect your rights.

7. Possible outcomes

After evidence and, if applicable, DNA testing, a court can:

• issue a judgment declaring you the decedent’s child (legal parentage);
• order that you are included in intestate distribution under the Probate Act if no valid will excludes you;
• confirm you as a beneficiary under a will or trust if the instrument names you or the court interprets intent accordingly (though challenges to wills have their own rules).

8. When a will or trust exists

If the decedent left a will that omits you, you may still be able to challenge it—but challenges depend on many factors (capacity, undue influence, fraud, whether the will validly disposes of the estate). If parentage is disputed, a paternity determination must usually be made before the court decides inheritance claims.

Practical checklist — what to do now

1. Confirm whether a probate for the decedent is open. Ask family members or search court probate records in the county where the decedent lived.
2. Request your birth record and ask whether an AOP was filed with Illinois Vital Records.
3. Gather documentary evidence (communications, photos, medical/school records, affidavits).
4. If possible, arrange a DNA test (with the alleged father or his close relatives). If the father is deceased, ask the estate representative about available biological samples or relatives for testing.
5. If an estate is open, notify the estate representative and file a timely claim or petition in probate if you intend to assert heirship.
6. Consult with a probate or family law attorney who handles paternity and estate claims in Illinois. They can file petitions, request testing, and represent you at hearings.

Helpful hints

• Preserve all evidence and make copies. Originals may be required in court.
• Get sworn affidavits from people who knew the decedent’s relationship to you—these can support your case while you arrange DNA testing.
• If finances are a concern, ask the court about fee waivers or seek legal aid organizations in Illinois that handle family and probate matters.
• Be proactive when an estate is opened: deadlines in probate can be short, and missing a deadline can forfeit rights.
• Remember that courts value genetic proof highly. When possible, obtain properly administered DNA tests through a court-approved lab to avoid disputes about chain-of-custody.
• Talk to the estate’s personal representative. Sometimes a timely, documented claim and an agreed DNA test can resolve the matter without prolonged litigation.