Lesbian parents have been around for a long time. Some men can be pregnant and give birth. But I assume you mean the issue being that they’d be alone, not the lack of a male parent. Being a single parent when you weren’t expecting to is hard. But of you’re prepared and equipped for it, go nuts. IVF is given to awful married parents. The parents’ aptitide isn’t a factor for couples, why should a standard suddenly exist for single people?