A Florida couple is suing their fertility doctor after they claimed a DNA test revealed the wrong sperm was used to create their IVF baby.

Natalie, 36, and Joshua Strong, 53, gave birth to a baby girl last year after two rounds of in vitro fertilization treatments at Brown Fertility Associates in Jacksonville.

However, a routine blood test on the newborn revealed she has a B-positive blood type, according to the couple's lawsuit.

Natalie's blood type is O Negative and Joshua's is A Negative, meaning it is biologically impossible for them to have a child with a positive blood type.

The couple filed a negligence lawsuit against the fertility clinic and their doctor, Dr Samuel Brown, on Thursday, claiming the wrong sperm was used to create their embryos.

'The report confirmed that Natalie is the biological mother of the daughter she carried and delivered, conceived from the embryo Brown Fertility transferred into her body, and that Joshua is not the biological father,' the court filing states.

'There is only one possible conclusion: Brown Fertility used the wrong sperm.'

At a press conference on Thursday announcing the lawsuit, the couple said learning their daughter was not biologically related to Joshua shattered their newborn bliss, First Coast News reported.

'It took away the euphoria of having a baby. I mean, this is going to affect us for the rest of our lives,' Natalie said. 

'It's a daily struggle with, you know, the emotional aspect of it 'cause, you know, you do have sadness and anger, and in the same day you also have joy and love,' Joshua added.

The couple claimed they paid 'tens of thousands of dollars' to Brown Fertility to have biological children together, the lawsuit claims.

Joshua previously had a vasectomy, so he had to undergo a painful sperm retrieval for the IVF process, the suit continued. 

'Joshua submitted to invasive surgery to retrieve sperm that, somewhere between the freezer and the petri dish, was substituted with the sperm of a man Brown Fertility cannot identify,' the filing stated.

According to the lawsuit, the couple was able to create seven embryos, and Natalie miscarried after the first transfer, but was able to carry the second transfer to term and gave birth on June 5, 2025.

Their lawsuit seeks $50,000 in damages and wants the clinic to be required to account for Joshua's sperm.

'We want to know what happened to his sperm. We want to make sure it was not used anywhere else,' Natalie said.

The couple's attorney, Rob Marcereau of the Fertility Law Group, told the Daily Mail they want to hold the clinic accountable and help prevent others from going through what they did.

'The Strongs filed this lawsuit to get answers and hold Dr. Brown and his clinic accountable for what happened,' Marcereau said.

'By sharing their story publicly, they also hope to help prevent another family from going through the same thing.'

The Daily Mail contacted Brown Fertility and Dr Brown for comment.