If you’re not talking about two sets of ᴛᴡɪɴꜱ in the same family, four children under the age of four may seem implausible. Three years after the birth of twin Bᴏʏs, a Sydney family welcomed the arrival of twin Girls.

Camilla and Madison Annagrove ᴛᴡɪɴꜱ are in 100,000 pairs.

Sophia and Paule Brown, who are thrilled parents, welcomed a second set of ɪᴅᴇɴᴛɪᴄᴀʟ twin daughters this week at Norwest Private Hospital in Bella Vista.

The Norwest Private Hospital also gave birth to their older brothers, Ethan and Harley, who are now three years old.

On September 6, a Wednesday, the ᴛᴡɪɴꜱ came. Madison arrived one minute after Camilla at 1.25 p.m., weighing 3.02kg, and Camilla at 3.12kg.

What’s more amazing is that neither set of ᴛᴡɪɴꜱ had in vitro fertilization (IVF), which increases the likelihood of multiple births.

The second time around, we were even more sᴛᴀʀᴛʟᴇd than we were the first.

Although ɪᴅᴇɴᴛɪᴄᴀʟ ᴛᴡɪɴꜱ are not genetically inherited, the four siblings are the only ᴛᴡɪɴꜱ in their families.

With Ethan and Harley, Mrs Brown, 32, had a normal birth; with Camilla and Madison, she underwent a cesarean. Both pairs of ᴛᴡɪɴꜱ were born without incident.

According to obstetrician Dr Norᴍᴀɴ Blumenthal, who delivered all the Brown children, the likelihood of having ɪᴅᴇɴᴛɪᴄᴀʟ ᴛᴡɪɴꜱ is one in 1,000. Having two sets of ɪᴅᴇɴᴛɪᴄᴀʟ ᴛᴡɪɴꜱ is even more unlikely.

If a number could be found, he continued, “it would be given one in 100,000 or so.

Mrs Brown was a “wonderful patient,” according to Dr Blumenthal.

He said, “She was really attuned with ᴛᴡɪɴꜱ. She read about it before getting Pʀᴇɢɴᴀɴᴛ for the first time, so she was ready from the start.

Mrs Brown, who was scheduled to leave the hospital Tuesday, described herself as “tired but good.”