But, when it comes to El Al, it turns out that asking one of its staff to store upright a canister containing frozen embryos in liquid nitrogen is perfectly normal.

That is exactly what happened to Esther Rubinstein on a flight from Australia to Israel.

For the 37-year-old is deputy head of the IVF laboratory at Jerusalem’s Shaare Zedek Medical Centre.

It is a role she has fulfilled for more than 10 years in a country where the number of couples seeking in vitro fertilisation, a process of fertilisation where an egg is combined with sperm outside the body, is high.

“The flight attendant on the El Al flight from Australia understood perfectly because she had been through the IVF process,” Manchester-raised Esther told me from her home in Jerusalem.

Esther didn’t take the conventional route into medicine.

One of 11 children born to Rabbi Berel Cohen and his wife Ruth, she was educated in Manchester at Broughton Jewish Cassel Fox Primary School and Beis Yaakov High School.

In 2001, she married Benny, whose father, Rabbi YY Rubinstein, holds something of a legendary status in the north-west, and they settled in Israel.

But they returned two years later when her mother-in-law fell ill.

And it was while back in her native city that Esther decided to read genetics at the University of Manchester, later taking a Master’s in the same subject.

The mother-of-three said: “I actually had a place to study software engineering, but I cancelled it because I got married and moved to Israel.

“Something about genetics had always interested me.”

In December, 2007, the family moved back to Israel and, a year later, Esther began work at Shaare Zedek’s IVF laboratory.

There, she was trained by Londoner Dr Baruch Brooks, one of the world’s leading experts in IVF.

In that time, a lot has changed when it comes to IVF.

Esther explained: “There is a lot of new technology. We have always grown the embryos in incubators with the right combination of temperature, carbon dioxide and oxygen to try and replicate the conditions in the womb.

“The disadvantage is that we have to remove the embryos daily to check their development. Now, we have incubators with built-in cameras so we can watch the embryos the whole time.

“It gives us the chance to see them develop and lets us look at things we would not have seen otherwise.”

The success rate in Israel is around 15 per cent — as in taking a baby home.

And, Esther said, the younger the woman, the higher chance there is of success and, while 35 per cent are likely to become pregnant, there is a 20 per cent chance they will miscarry.

Esther said: “We have patients from all over the world and the largest pre-implantation genetic diagnosis programme in Israel.”

And, while she believes she is doing her bit for the continuation of the Jewish people, Muslim and Christians couples also use the hospital’s IVF service, as do those foreign workers who hold medical insurance.

“Jews and Muslims in Israel, even if they are not religious, tend to have four or five children, as opposed to the UK, where the average family has 2.5 children,” Esther said.

“In the case that a Jewish or Muslim woman wants to have kid number four, five or six, they may struggle to conceive, so they will come to us.”

There has also, in recent years, been a trend of Jewish women wanting a baby, but not wanting to marry, nor do they have a partner.

But, Esther explained, Machon PUAH, the leading halachic authority in Israel when it comes to fertility treatment, recommends taking sperm from a non-Jewish man in these instances.

She added: “The baby will, obviously, still be Jewish. If the sperm comes from a non-Jewish man, there is less chance that, in the future, the child will meet or maybe even marry its half-sibling.

“The amount of Jewish men willing to donate sperm is also very small.”

The laboratory does not do anything without religious backing, either.

“Shaare Zedek is a religious hospital,” Esther said. “The laboratory, for example, is under constant halachic supervision — we cannot do any work without them.

“There is a set of halachic supervisors who make sure the right eggs go with the right sperm and that the right embryos are transferred to the right women.”

The laboratory is open six days a week and Esther, who works five of them, is usually there by 7.30am where she checks if the eggs have fertilised.

She will then go on to defrost embryos from previous cycles for transfer to the patient and later in the day remove external cells from retrieved eggs to check if they are mature, which means she can then inject them in the afternoon.

“Some men also have a low or non-existent sperm count, so we have techniques where we search through a sample, drop by drop, to find literally one or two sperm which we inject into the eggs,” Esther continued.

As Ashkenazim and Sephardim are both susceptible to certain illnesses, she dons her geneticist cap.

“If both parents are carriers of a particular disease, we test the embryos and will then only transfer the healthy ones,” Esther said.

“A woman or man can also be a carrier of a dominant disease, so we try to stop it being transferred to the next generation.”

* If you would like advice from Esther on fertility matters, email esterrub@szmc.org.il

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