Is there really artificial sperm? Women no longer need male sperm to get pregnant

It's the season for couples to show off their love again. However, recent studies have shown that women can produce sperm, and pregnancy no longer requires men. Female lesbian couples are not far away. So is there really artificial sperm? Do women really not need male sperm to get pregnant?

No need for males to produce sperm

Spring is here, and it's time to prepare gasoline and torches. However, for scientists with brains and technology, they can do something more "mean", such as inventing a technology that can produce sperm without men to deal with the increasingly serious problem of heterosexual love.

Researchers are indeed trying to establish a new route for preparing sperm, but the reason for doing so is not because they are tired of seeing couples showing off their affection. In fact, scientists have had this idea for more than a year or two.

Two years ago, a group of Israeli scientists induced human embryonic stem cells to differentiate into primordial germ cells in vitro. A group of Japanese scientists went a step further and injected the mouse primordial germ cells induced in vitro into the testicles of male mice, and with the help of the physiological environment in the testicles, these induced primordial germ cells developed into functional sperm.

The birth of these results means that scientists can now use iPS technology to induce a female mouse's somatic cells into pluripotent stem cells, and then induce these pluripotent stem cells into primordial germ cells in vitro. By injecting these female-derived primordial germ cells into the mouse testicles to develop into sperm, they can use these sperm to produce mouse offspring that do not contain any male-derived genetic material. Are you afraid?

Don't be afraid, because the scarier part is yet to come - scientists have noticed that although males do not provide genetic material in the above process, they still provide testicles. So recently, the team of Academician Zhou Qi and Researcher Zhao Xiaoyang from the Institute of Zoology of the Chinese Academy of Sciences and the team of Professor Sha Jiahao from Nanjing Medical University have cooperated to eliminate the last bit of male presence.

In a study recently published in Cell Stem Cell, they induced mouse embryonic stem cells into primordial germ cells in vitro, and then co-cultured these primordial germ cells with cells from testicular tissue in vitro, thereby directly inducing them into cells with sperm function in vitro, which are similar to round spermatids in shape. They are not mature sperm with tails that people imagine, but they are very close.

Although Academician Zhou Qi and others pointed out that this move was to facilitate in vitro observation of sperm formation and treatment of male infertility, this did not stop the results from causing a stir in public opinion. Many experts in the field of reproduction and stem cells have a positive attitude towards this. Israeli stem cell scientist Jacob Hanna said: "This is a super exciting and important result."

More discussions also centered on the clinical prospects and ethical issues of this research. Dr. Vittorio Sebastiano of Stanford University believes that this is a milestone, and although it is still a long way from clinical application, we cannot predict how the gametes obtained by this method will affect future generations, and this topic is worth discussing.

Considering the huge differences between human and mouse germ cells, it is probably too early to say "no more men". However, the pace of technological progress never stops. Whether infertile men or women who want children can benefit from it, and what impact such assisted reproductive technology will have on our society, I believe time will give the answer.

How long does it take for sperm and egg to combine?

The process of sperm and egg combining together is the fertilization process. The fertilization process takes about 24 hours. When an activated sperm enters the zona pellucida of the egg cell, the fertilization process begins. When the chromosomes of the sperm and egg fuse together, it marks the completion of the fertilization process.

During intercourse, the man ejaculates into the woman's vagina. The sperm moves forward by swinging its tail and soon swims to the cervical canal. The sperm releases protein-dissolving enzymes to dissolve the cervical mucus and moves from the uterine cavity to the ampulla of the fallopian tube. At the final stop, the ampulla of the fallopian tube, it waits to combine with the egg. It takes only a few minutes for the sperm to reach the fallopian tube from the vagina, and 4-6 hours at the latest, usually 1-1.5 hours.

Sperm survival time

We know that the survival time of an egg is generally 24 hours, which is about 1 day. However, the survival time of sperm in a woman's body is longer than that of an egg, generally up to 2-3 days, and in some cases even longer. Studies have shown that human sperm can only survive for a few minutes in a natural environment outside the body.

The sperm that directly enters the female body can still maintain vigorous vitality due to the relatively suitable environment, and its reproductive ability cannot be ignored within 2 days. This is probably the result of natural selection and evolution. The magical time difference also provides more possibilities for sperm and egg to meet and become fertilized eggs.

Therefore, if you are a woman who does not want to get pregnant for the time being, it is best to add a few extra days when calculating the ovulation period and the dangerous period, and it is also best to take precautions three days before the ovulation period. Of course, for those who are planning to get pregnant, you can also act in advance to increase your chances.